JPH08134441A - Phosphor particles - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide phosphor particles that are particularly excellent in moisture resistance, water resistance, light resistance, etc., and can maintain the required performance for a long period of time without the brightness of the phosphor particles being substantially reduced due to blackening. To do. [Configuration] The phosphor particles may be obtained by dry-mixing the inorganic dispersion type phosphor particles and the fluorine-containing vinyl polymer particles to coat the inorganic dispersion type phosphor particles with the fluorine-containing vinyl polymer, or thereafter by using an ultraviolet absorber. The particles are dry-mixed with the particles and further coated with an ultraviolet absorber.

Description

Detailed Description of the Invention

[0001]

The present invention relates to phosphor particles,
More specifically, it relates to phosphor particles having excellent moisture resistance, water resistance, light resistance and the like.

[0002]

2. Description of the Related Art In recent years, fine phosphor particles have been used as an electroluminescent body (that is, electroluminescence, hereinafter referred to as "EL") in the fields of backlights of liquid crystal display devices, fluorescent display devices, and the like. However, in such a phosphor particle, it is necessary to have sufficient moisture resistance, water resistance, light resistance, chemical resistance, solvent resistance, heat resistance, etc. in a well-balanced manner, and therefore, the particle Material selection / modification,
Various improved techniques such as treatment of phosphor particles have been proposed. For example, phosphor particles such as zinc sulfide doped with various metal ions used for EL are apt to absorb moisture particularly under voltage application, and when moisture is absorbed, the surface thereof is blackened and the brightness is lowered, and the useful life is impaired. Moisture resistance and water resistance are important, and even if the phosphor particles come into contact with impurities (such as iron, nickel, chromium, etc.) in the insulating layer or the transparent electrode, they are also blackened and the brightness decreases. There is. In particular, a relatively large display device such as a traffic sign using a EL element or a vehicle emergency stop plate is usually manufactured by connecting several unit elements in a plane. There is a problem that the phosphor particles gradually become blackened toward the end, the life of the display device is shortened, and the burden on maintenance is extremely large, and the decrease in brightness due to the blackening of the phosphor particles is suppressed as much as possible. It is highly desirable to extend the useful life of the particles. Therefore, a moisture-resistant / water-resistant protective coating is formed on the surface of the phosphor particles for EL elements, but such a protective coating needs light resistance and heat resistance in use. Solvent resistance is also required in the processing process. Conventionally, a so-called microencapsulation method has been known as a method for coating phosphor particles, and various methods such as a coacervation method, a spray drying method, a fluidized bed coating method, and a polymerization coating method have been proposed. There is. However, with these methods, moisture resistance
Not only is it difficult to obtain not only water resistance but also light resistance, chemical resistance, solvent resistance, heat resistance, etc., it is difficult to obtain particles, and the durability of the coating layer and the adhesion to phosphor particles However, it is difficult to maintain the required performance for a long time. On the other hand, especially moisture resistance and water resistance of phosphor particles for EL elements,
As a coating method for improving solvent resistance and the like, a method of coating with water glass, polydimethylsiloxane, boron nitride, fluorocarbon or the like (for example, Japanese Patent Laid-Open No. 2-113085).
(See Japanese Patent Laid-Open No. 239795), a method of coating with a metal alkoxide (for example, alkoxysilane) in which a pigment is dispersed (see, for example, JP-A-63-276892), a method of coating with a metal oxide (for example, Japanese Patent Laid-Open No. 1-239795, JP-A-1-
315989), a method of coating with hydrophobic silica particles (see, for example, JP-A-63-23987), and the like. However, these methods are also unsatisfactory in terms of overall performance including moisture resistance, water resistance, light resistance, and the like, and the adhesion between the phosphor particles and the coating layer is still insufficient.

[0003]

The present invention is particularly suitable for moisture resistance and
An object of the present invention is to provide a phosphor particle having excellent water resistance, light resistance, etc., which can maintain the required performance for a long period of time without substantially lowering the brightness due to blackening of the phosphor particle.

[0004]

The gist of the present invention is as follows. First, the inorganic dispersion type phosphor particles are mixed with fluorine-containing vinyl by dry-mixing the inorganic dispersion type phosphor particles and the fluorine-containing vinyl polymer particles. Phosphor particles (hereinafter referred to as "first invention") coated with a base polymer.

Secondly, the gist of the present invention is to dry-mix the inorganic dispersion type phosphor particles and the fluorine-containing vinyl polymer particles to coat the inorganic dispersion type phosphor particles with the fluorine-containing vinyl polymer, The phosphor particles (hereinafter, referred to as "second invention") are obtained by being dry-mixed with the ultraviolet absorber particles and further coated with the ultraviolet absorber.

The present invention will be described in detail below. This will clarify the objects, configurations and effects of the present invention. Inorganic Dispersion Phosphor Particles Examples of the inorganic dispersion phosphor particles used in the first invention and the second invention (hereinafter referred to as “base phosphor particles”) include, for example, zinc sulfide, zinc sulfide-cadmium sulfide system,
Examples thereof include particles of zinc oxide, zinc oxide-silicon oxide-based particles, and the like. These base phosphor particles may be previously subjected to a doping treatment with various metal ions. Examples of ions used for such doping include copper sulfide, aluminum ion, silver ion, manganese ion and the like for zinc sulfide particles; zinc sulfide-
Copper ions, aluminum ions, etc. for cadmium sulfide-based particles; zinc ions, etc. for zinc oxide; zinc oxide-
Examples of the silicon oxide type include manganese ion and arsenic ion, and these metal ions are usually used in the form of chlorine salt, bromine salt or iodine salt. The base phosphor particles are formed by kneading and mixing two or more materials, and then granulating,
It may be classified, and the properties of the base phosphor particles are
Generally crystalline, but may be amorphous in some cases. Further, the base phosphor particles may be hollow or porous. The base phosphor particles generally have an average particle size (R ₁ )
The larger the value, the lower the brightness and the longer the life tends to be.
Therefore, the average particle diameter (R ₁ ) is appropriately selected according to the intended use of the obtained base phosphor particles, desired characteristics, etc., but for example, in the case of copper ion-doped zinc sulfide particles, it is usually 10
˜50 μm, preferably 20-40 μm. In addition,
When the shape of the base phosphor particles is non-spherical, the average particle size of the particles is based on the spherical equivalent diameter. The more uniform the particle size of the base phosphor particles, the more preferable, but the standard deviation of the particle size distribution is usually ± 40% or less, preferably ± 20% or less of the average particle size. Further, the shape of the base phosphor particles is
Usually, it has an irregular shape, but it can also have a specific shape such as a sphere, an ellipse, or a hexagonal crystal. The method for preparing the base phosphor particles as described above is not particularly limited, for example, rolling granulation, fluidized bed granulation, stirring granulation, crushing / pulverization granulation,
Physics such as compression granulation, extrusion granulation, melt granulation, mixed granulation, spray cooling granulation, spray drying granulation, precipitation / precipitation granulation, freeze drying granulation, suspension aggregation granulation, drop cooling granulation The granulation method is appropriately selected and granulated. Needless to say, a commercially available product can be used as the base phosphor particles. The base phosphor particles may be used alone or in combination of two or more.

Fluorine-Containing Vinyl Polymer Particles Next, the fluorine-containing vinyl polymer used in the first and second inventions (hereinafter referred to as "fluorine-containing polymer").
Say. ) Are, for example, homopolymers of fluorine-containing vinyl-based monomers such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, and copolymers of two or more of these fluorine-containing vinyl-based monomers. Examples thereof include polymers. These fluoropolymers are components that impart required moisture resistance and water resistance to the base phosphor particles. in this case,
Other moisture-proof polymers, such as polyethylene, polypropylene, and polyethylene terephthalate, cannot ensure the high degree of moisture resistance and water resistance required for various display devices. Particularly preferred fluorine-based polymer has a monomer composition (mol%) of usually 0 to 75/0 to 85/0 to 30,
It is preferably a tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer of 10 to 50/20 to 80/10 to 25. The fluoropolymer can be produced by an appropriate method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, blown polymerization and the like. The molecular weight of the fluoropolymer is not particularly limited and is usually 5,000 to 300,000, preferably 10,000 to 150,000. The fluoropolymer in the first invention and the second invention is used as particles. The average particle size (R
₂ ) is appropriately selected depending on the size of the base phosphor particles, the intended use of the obtained phosphor particles, etc., but is usually 3 nm to 5 nm.
μm, preferably 0.1 to 1 μm, and the particle size ratio (R ₂ / R ₁ ) between the fluoropolymer particles and the base optical body particles is usually
It is 1/10 or less. When the fluoropolymer particles have an asymmetrical shape such as an ellipse, the particle diameter is based on the equivalent spherical diameter. In this case, if the average particle diameter (R ₂ ) of the fluorine-based polymer particles is less than 3 nm, the particles are likely to agglomerate and the coating layer may be non-uniform, and if it exceeds 5 μm, the base phosphor is generally used. The fluoropolymer particles are too large as compared with the particles, and it tends to be difficult to obtain uniform phosphor particles. The standard deviation of the particle size distribution of the fluoropolymer particles is usually ± 40% or less of the average particle size, preferably ± 20% or less. The smaller this standard deviation is,
The fluoropolymer can uniformly coat the base phosphor particles, but the technical constraint is smaller than that of the base phosphor particles. This means that even if the particle size distribution of the fluoropolymer particles is somewhat wide, for example, in the coating process by dry mixing,
This is because the particles can be uniformly integrated and the surface of the coating layer made of a fluoropolymer can be sufficiently smoothed. The shape of the fluoropolymer particles is preferably spherical, but like the standard deviation of the particle size distribution, there is no limitation as much as the base phosphor particles, and the fluoropolymer particles are hollow bodies or porous bodies. You can also The method for preparing the fluoropolymer particles as described above is not particularly limited, for example, various physical granulation methods exemplified for the base phosphor particles and emulsion polymerization,
A chemical granulation method such as suspension polymerization is appropriately selected for granulation. Needless to say, commercially available products can be used as the fluoropolymer particles. The fluoropolymer particles may be used alone or in admixture of two or more.

Hydrogen Sulfide Absorber Particles In the first and second inventions, for example, when the base phosphor particles are made of cuprous chloride-doped zinc sulfide,
At least the hydrogen sulfide absorbent particles are preferably included in the coating layer that is in contact with at least the surface of the phosphor particles. As such hydrogen sulfide absorbent particles, for example, particles containing hydrogen sulfide absorbent composed of an unsaturated compound as a main component, and optionally a basic compound, an adsorbent, a desiccant, a catalyst, a particle containing auxiliary components such as a carrier. Can be mentioned. Examples of the unsaturated compound include unsaturated aliphatic compounds having a polar group such as a hydroxyl group, an aldehyde group, a ketone group, a carboxyl group, a sulfonic acid group, an amino group, and an etheric oxygen atom; for example, oleic acid, linoleic acid, and linole. Unsaturated fatty acids such as acids and metal salts thereof; animal or vegetable oils that are triglycerides of the unsaturated fatty acids; and aliphatic conjugated diene hydrocarbons such as butadiene and isoprene, and triple bond-containing aliphatic hydrocarbons such as acetylene ( Examples thereof include a (co) polymer and a derivative of the (co) polymer, and polyisoprene having a sulfonate group is particularly preferable. These unsaturated compounds may be used alone or in admixture of two or more. Among the auxiliary components, examples of the basic compound include oxides, hydroxides, carbonates and organic acid salts of alkali metals or alkaline earth metals; saturated aliphatic amino compounds and the like. Examples of the adsorbent include silica gel, activated carbon, activated clay, zeolite, perlite and the like. Examples of the desiccant include activated alumina, anhydrous calcium sulfate, silica gel, magnesium oxide, calcium oxide and the like. The catalyst is to increase the hydrogen sulfide absorption rate of the hydrogen sulfide absorbent, as an example,
Transition metals and / or their compounds, specifically metals such as iron, cobalt, nickel, chromium and copper, and their sulfates, chlorides, nitrates, organic acid salts, compounds such as complex salts with amino compounds, etc. Can be mentioned. Further, the carrier carries and / or absorbs each of the components used in the hydrogen sulfide absorbent to maintain the hydrogen sulfide absorbent particles in a predetermined shape and increase the contact area of the particles with hydrogen sulfide. It increases the absorption rate of hydrogen sulfide, and examples thereof include particles of the adsorbent. Commercial products of the hydrogen sulfide absorbent containing the unsaturated compound and the auxiliary component are "RP" manufactured by Mitsubishi Gas Chemical Co., Inc.
(Registered trademark), which is preferably crushed and used in the first and second inventions. The smaller the average particle size (R ₃ ) of the hydrogen sulfide absorbent particles is, the larger the surface area is, which is preferable, but it is usually 10 nm to 5 μm, preferably 0.1 to 3 μm. The particle size ratio (R ₃ / R ₁ ) to the phosphor particles is usually 1/10 or less. When the hydrogen sulfide absorbent particles are non-spherical, the average particle diameter is based on the equivalent spherical diameter. In this case, it becomes difficult to form a uniform coating layer even if the average particle diameter (R ₃ ) of the ultraviolet absorbent particles is less than 10 nm or more than 5 μm,
It tends to be difficult to develop a sufficient hydrogen sulfide absorption capacity. The standard deviation of the particle size distribution of the hydrogen sulfide absorbent particles is usually ± 40% or less of the average particle size, preferably ± 20.
% Or less. The smaller the standard deviation, the more uniform the coating layer containing the particles. The hydrogen sulfide absorbent particles are preferably spherical in shape, but can optionally have a non-spherical shape. The method for preparing the hydrogen sulfide absorbent particles as described above is not particularly limited,
For example, various physical granulation methods exemplified for the base phosphor particles are appropriately selected and granulated. The hydrogen sulfide absorbent particles may be used alone or in admixture of two or more.

Ultraviolet Absorber Particles The ultraviolet absorber particles used in the second invention effectively absorb and block ultraviolet rays (wavelengths of about 400 nm or less) to suppress the action of ultraviolet rays on the base phosphor particles. The particles can be extinguished, and may be inorganic particles or organic particles, but inorganic particles are preferable from the viewpoint of ultraviolet blocking property, durability and the like. Examples of such inorganic particles include zinc oxide, titanium oxide, and cerium oxide. The smaller the average particle diameter (R ₄ ) of the ultraviolet absorbent particles is, the larger the surface area is, which is preferable, but usually 5 nm to 1 μm,
It is preferably 10 nm to 0.1 μm, and the particle size ratio (R ₄ / R ₁ ) between the ultraviolet absorbent particles and the base phosphor particles is usually 1/10 or less. In addition, the average particle diameter when the ultraviolet absorbent particles are non-spherical is based on the equivalent spherical diameter. In this case, the average particle diameter (R ₄ ) of the UV absorber particles is 5n
If it is less than m, the particles tend to agglomerate and it may be difficult to form a uniform coating layer, and if it exceeds 1 μm, the ultraviolet blocking property of the coating layer made of an ultraviolet absorber tends to decrease. . The standard deviation of the particle size distribution of the ultraviolet absorbent particles is usually ± 40% or less of the average particle size, preferably ± 2.
0% or less. The smaller the standard deviation, the more uniform the coating layer made of the ultraviolet absorber. The UV absorber particles are preferably spherical in shape, but can also be non-spherical in some cases. The method for preparing the ultraviolet absorbent particles as described above is not particularly limited, and for example, various physical granulation methods exemplified for the base phosphor particles are appropriately selected and granulated. Needless to say, commercially available products can be used as the ultraviolet absorbent particles. The ultraviolet absorbent particles may be used alone or in combination of two or more.

Phosphor Particles (I) The phosphor particles constituting the first invention and used in the second invention (hereinafter referred to as "phosphor particles (I)") are the base phosphor particles and fluorine. The phosphor particles are coated with a fluoropolymer by dry-mixing with the polymer particles (hereinafter, this coating layer is referred to as a "fluorine coating layer"). In this case, the base phosphor particles coated with the fluoropolymer may have a coating layer formed in advance. The thickness of the fluorine-based coating layer is appropriately selected according to the average particle size of the base phosphor particles, the desired size of the phosphor particles (I), etc., but is usually 0.1 to 5 μm, preferably It is 0.3 to 2 μm. The weight ratio of the base phosphor particles and the fluoropolymer particles in the phosphor particles (I) is appropriately selected according to the average particle diameter to be combined, the desired film thickness of the fluoro coating layer, and the like. The amount of the fluoropolymer particles is usually 1 to 100 parts by weight, preferably 3 to 50 parts by weight, per 100 parts by weight of the base phosphor particles. As a method for forming such a fluorine-based coating layer, for example, the base phosphor particles and the fluorine-based polymer particles are dry-mixed under conditions in which crushing and deformation of the phosphor particles do not substantially occur, A method of applying at least a compressive force and a shearing force to the particles to bond and bond the fluoropolymer particles onto the phosphor particles (hereinafter referred to as “dry coating method (I)”) can be mentioned. it can. In this case, an impact force and / or a twisting friction force can be further applied during mixing, and it is particularly preferable that the twisting friction force is applied together with the compression force and the shearing force. Further, in the dry coating method (I), it is preferable to mix them in a state where the water content is low (for example, in an inert gas atmosphere or in dry air having a relative humidity of 20% or less). Dry coating method
In (I), by performing the mixing so that the crushing and the deformation of the base phosphor particles do not substantially occur, the phosphor particles can retain the original size and shape during the treatment process, and the uniform It becomes possible to obtain phosphor particles having a coating layer. However, in the dry coating method (I), even when only the thin layer portion of the surface of the base phosphor particles is deformed, it can be considered that the crushing and the deformation are not substantially caused. In the dry coating method (I), the "compression force" means
It means a force mainly acting in the radial direction of each particle, which acts when the base phosphor particles and the fluorine-based polymer particles are pressed against each other or the mixing container wall, the stirring blade, etc. Further, the "shearing force" means a force for shearing the particle layer existing in the mixing space, and is, for example, a force generated in the vicinity of a stirring blade of a stirrer or in a region where the speed difference between particles is large. Further, the "impact force" means a force that acts on each particle in a short time when the particles collide with each other or with a wall of a mixing vessel, a stirring blade, etc., and the "twisting friction force" means, for example, 2 It means a twisting force (torsion force) accompanied by friction acting on the fluorine-based polymer particle layer existing in the roll gap of the book due to the difference in roll rotation speed and the roll pressure. The specific mixing method adopted in the dry coating method (I) is
For base phosphor particles and fluoropolymer particles,
There is no particular limitation as long as it can apply at least a compressive force and a shearing force. As such a mixing method, for example, a method using a mortar; a method using a rotary container type solid mixer such as an inclined cylinder type tumbler, a V type tumbler, and a double cone type tumbler; a ribbon type mixer, a rotary disk type mixer Method using a mechanical stirring type solid mixer such as;
Method using complex type solid mixer such as V-type tumbler with internal blade, double-cone tumbler with internal blade; kneader mixer, internal mixer, Mueller mixer,
Examples thereof include a method using a kneading machine such as a Henschel mixer and a roll mill; a method using a mechanical stirrer such as a turbine type stirrer and a bull margin type stirrer; and an impact force by a high-speed air flow or a method using mechanical stirring. Among these mixing methods, an impact force due to a high-speed air flow or a mixing method using mechanical stirring with it is preferable, and an apparatus therefor is, for example, a hybridizer manufactured by Nara Machinery Co., Ltd., an Ongmill manufactured by Hosokawa Micron Corporation. Etc. can be mentioned. In the dry coating method (I), which of the compressive force and the shearing force, or the impact force and / or the twisting friction force which act depending on the action mainly acts depends on the stirring speed, the mixing method (stirring blade, roll,
Although various mixing conditions (such as air flow) are complicatedly related and cannot be generally stated, the compressive force and the shearing force are forces acting in all the exemplified mixing methods. On the other hand, the impact force works effectively when using, for example, a high-speed stirrer or a high-speed air flow, and the twist friction force works effectively, for example, when mixing between two rolls or by a meshing screw. In the dry coating method (I), even if the base phosphor particles and the fluorine-containing polymer particles are simultaneously, collectively or stepwise or continuously charged into the mixer, the base phosphor particles and / or the fluorine-containing polymer particles are not added. If a portion of the system-based polymer particles is charged first, and the remaining particles are charged collectively or stepwise or continuously, either one of the base phosphor particles and the fluorine-based polymer particles is further added. The whole amount may be charged first, and the other particles may be charged collectively or stepwise or continuously, but the base phosphor particles and the fluoropolymer particles may be charged simultaneously in the mixer, or It is preferable that all of the base phosphor particles be charged first, and the fluorine-based polymer particles be charged all at once or stepwise or continuously. At the time of mixing in the dry coating method (I), the base phosphor particles are usually positively (+) charged, and the fluoropolymer particles are negatively (−) charged. Cohesion and bonding proceed rapidly. In this case, by charging the mixed system under insulation, it is possible to accelerate the charging of the particles. The mixed system usually does not have to be actively heated or cooled, but may be heated or cooled if necessary. The mixing time in the dry coating method (I) depends on the mixing temperature,
The mixing rate is appropriately set according to the mixing conditions such as the stirring speed and the mixing method. In the mixing method using a mortar, for example, 30 to 12
It is preferably about 0 minutes. The mixing time in other mixing methods may be shorter than that in the case of using a mortar, but it needs to be adjusted according to the individual mixing method. In this case, an appropriate mixing time can be selected by experiment. Furthermore, the administration power at the time of mixing is appropriately set according to the mixing conditions, but a suitable administration power can be selected by experiment. By dry-mixing the base phosphor particles and the fluoropolymer particles in this manner, momentarily, for example, at the contact point between the particles or at the contact point between the particles and the mixing container wall, the stirring blade, etc. At least a part of the fluorine-based polymer particles or at least the surface layer of the fluorine-based polymer particles is softened and / or melted due to the generation of high heat around 1000 ° C., and each softened and / or melted particle is present in some cases. Along with the softened and unmelted fluoropolymer particles, it is uniformly integrated and firmly adhered to the surface of the base phosphor particles,
It will be bonded to form a fluorine-based coating layer having excellent properties. The dry coating method (I) basically comprises the steps described above, but after the required fluorine-based coating layer has been formed, such mixing treatment is further continued to form on the surface of the base phosphor particles. It is preferable to smooth the surface of the obtained fluorine-based coating layer. That is, since the outermost layer of the phosphor particles (I) is composed of a fluorine-based coating layer having excellent moisture resistance and water resistance, the phosphor particles themselves have extremely low hygroscopicity and have good handling properties as powder particles. By smoothing the surface of the fluorine-based coating layer, the fluidity and handling property can be further improved, and the weight and size of the handling equipment can be reduced, which is extremely advantageous industrially. Continuing such a mixing treatment can be carried out basically in the same manner as the mixing in the dry coating method (I). Appropriate treatment conditions are the surface properties of the phosphor particles (I) to be treated. Can be appropriately set through experiments. Phosphor particles (I) thus obtained
Based on the excellent moisture and water resistance of the fluorine-based coating layer, the effect of moisture such as water vapor in the air and rainwater on the base phosphor particles is effectively blocked, resulting in blackening of the phosphor particles. The phenomenon is remarkably suppressed, and for example, the required brightness as the phosphor particles for EL elements can be maintained for a long time.

Further, in the phosphor particles (I), at least the coating layer which is in direct contact with the surface of the base phosphor particles may contain the hydrogen sulfide absorbent particles. Such a phosphor particle (I) is used, for example, by mixing hydrogen sulfide absorbent particles with fluorine-based polymer particles and using the fluorine-based coating layer containing hydrogen sulfide absorbent particles (hereinafter referred to as “fluorine-based mixed coating layer”). ), A fluorine-based coating layer containing a relatively high proportion (preferably 1 to 10% by weight) of hydrogen sulfide absorbent particles on the surface of the base phosphor particles in advance (hereinafter, "fluorine-based preliminary coating layer"). It can be obtained by a method of forming a fluorine-based coating layer after the formation of (). These and methods can be carried out basically in the same manner as the dry coating method (I). In this case, the amount of hydrogen sulfide absorbent particles used is appropriately selected according to the type of particles, the average particle size, etc., but is usually 0.1 to 5% by weight with respect to the base phosphor particles. It is preferably 0.5 to 3% by weight. The film thickness of the fluorine-based mixed coating layer formed by the above method is the same as that of the fluorine-based coating layer in the phosphor particles (I) not using the hydrogen sulfide absorbent particles. Further, the film thickness of the fluorine-based preliminary coating layer formed by the method of, the average particle size of the base phosphor particles,
The phosphor particles (I) are appropriately selected according to the use purpose, etc.,
Usually 50 nm to 1 μm, preferably 0.1 to 0.5 μm
m, and the film thickness of the fluorine-based coating layer on the fluorine-based preliminary coating layer is within the range of the film thickness of the fluorine-based coating layer shown for the phosphor particles (I) not using the hydrogen sulfide absorbent particles, It is appropriately selected according to the film thickness of the fluorine-based preliminary coating layer. Such a phosphor particle (I) whose coating layer that is in direct contact with the surface of the base phosphor particle contains hydrogen sulfide absorbent particles is based on the hydrogen sulfide absorption effect of the coating layer, for example, a reaction between zinc sulfide and water. It is considered that the blackening phenomenon of the base phosphor particles due to the action of hydrogen sulfide generated by is effectively suppressed, and the excellent moisture resistance of the fluorine-based mixed coating layer or the fluorine-based coating layer mainly composed of the fluorine-based polymer. -In combination with the water resistance effect, for example, the required brightness as phosphor particles for EL elements can be maintained for a longer period of time. The average particle diameter of the phosphor particles (I) of the first invention is usually 10 to 60 μm.
m, preferably 20 to 50 μm. In the phosphor particles (I) of the first invention, each coating layer is firmly fixed and bonded even when dispersed in water and subjected to ultrasonic waves, for example, EL
Even when the device is manufactured or used for a long period of time, these coating layers do not peel off or fall off, and the required performance can always be stably exhibited.

Here, the preferable phosphor particles (I) in the first invention will be illustrated more specifically below. That is, preferred phosphor particles (I) are (a) base phosphor particles having an average particle size of 20 to 40 μm and having a standard deviation of particle size distribution of ± 20% or less of the average particle size, such as zinc sulfide particles, Fluorine-based polymer is monomer composition (mol%) 0 to 50/20 to 80
The average particle size 2 is composed of a tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer of / 10 to 35 and the film thickness of the fluorine-based coating layer is 0.3 to 2 μm.
Particles having a particle size of 0 to 44 μm, and particularly preferable phosphor particles (I) are (b) base phosphor particles having an average particle diameter of 20 to 40.
The particle size distribution standard deviation of μm is ± 20% or less of the average particle size of particles such as zinc sulfide, the hydrogen sulfide absorbent is polyisoprene having a sulfonate group, and the fluorine-based polymer is monomer composition (mol %) 0-50 / 20-80 / 1
Consisting of 0 to 25 tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer, 1 to 1
Particles having an average particle size of 20 to 44 μm in which the film thickness of the fluorine-based preliminary coating layer containing 0% by weight of hydrogen sulfide absorbent is 0.1 to 0.5 μm, and the film thickness of the fluorine-based coating layer is 0.3 to 2 μm. Is.

Phosphor Particles (II) Next, the phosphor particles of the second invention (hereinafter referred to as "phosphor particles (I
I) ”. ) Is a phosphor particle (I) of the first invention, preferably a phosphor particle (I) whose coating layer in direct contact with the surface of the base phosphor particle contains hydrogen sulfide absorbent particles, and ultraviolet absorbent particles. By dry-mixing, the phosphor particles (I) are further coated with an ultraviolet absorber (hereinafter, this coating layer is referred to as "ultraviolet absorbing coating layer"). The amount of the ultraviolet absorber particles used in the phosphor particles (II) depends on the size of the phosphor particles (I), the phosphor particles (I
Although it is appropriately selected depending on the use of I) and the like, it is usually 0.05 to 3% by weight, preferably 0.1 to 1% by weight, based on the base phosphor particles. As a method of forming the ultraviolet absorbing coating layer, for example, the phosphor particles (I) and the ultraviolet absorbent particles are mixed under conditions under which crushing and deformation of the phosphor particles (I) do not substantially occur. A method in which at least a compressive force and a shearing force are applied to the particles to bond and bond the ultraviolet absorber particles onto the fluorine-based mixed coating layer or the fluorine-based coating layer of the phosphor particles (I) (hereinafter,
It is called "dry coating method (II)". ).
In this case, an impact force and / or a twisting friction force can be further applied during mixing, and it is particularly preferable that the twisting friction force is applied together with the compression force and the shearing force. In the dry coating method (II), mixing is performed so that the phosphor particles (I) are not crushed or deformed substantially, so that the phosphor particles (I) retain their original size and shape during the treatment process. As a result, it becomes possible to obtain uniform phosphor particles (II). However, even when only the thin layer portion of the surface of the phosphor particles (I) is deformed, it can be considered that the crushing and the deformation are not substantially caused.
Such a dry coating method (II) is basically the dry coating method described above.
It can be carried out in the same manner as in (I). The ultraviolet absorbent particles in the ultraviolet absorbing coating layer adhere to the fluorine-based mixed coating layer or the fluorine-based coating layer located at the outermost layer of the phosphor particles (I) depending on the specific treatment conditions of the dry coating method (II). Of the individual phosphor particles (II), which can be at least one of the existing state, that is, the state in which they are partially embedded in these coating layers, or the state in which they are completely embedded in these coating layers. The presence state of the absorbent particles can be appropriately selected by experiments. In the phosphor particles (II), the presence states of and are preferable, and the presence state of is particularly preferable. That is, when the ultraviolet absorber particles at least partially protrude outside the coating layer located in the outermost layer, the fluidity of the phosphor particles (II) is high,
It is industrially advantageous, and it is preferable that the ultraviolet absorber particles are at least partially embedded in the coating layer located in the outermost layer.
The particles are firmly fixed and bonded to the coating layer. The phosphor particles (II) thus obtained are based on the moisture resistance / water resistance of the fluorine-containing coating layer or the fluorine-containing coating layer and the ultraviolet blocking ability of the ultraviolet absorbing coating layer, and the moisture content of the base phosphor particles. As a result of substantially blocking both the effects of ultraviolet rays and ultraviolet rays, it is possible to extremely effectively suppress the blackening phenomenon of the base phosphor particles due to these effects,
The required brightness as the phosphor particles for EL devices can be maintained for a particularly long period of time. Further, in a preferred aspect of the second invention, the hydrogen sulfide absorbing action of the fluorine-based preliminary coating layer containing the hydrogen sulfide absorbent particles also contributes, and the life is further extended. The average particle size of the phosphor particles (II) of the second invention is substantially the same as the average particle size of the phosphor particles (I) of the first invention. The phosphor particles (II) of the second invention are
For example, even when dispersed in water and subjected to ultrasonic waves, each coating layer is firmly fixed and bonded, and for example, each coating layer may peel off or fall off even during manufacturing of the EL element or during long-term use. Therefore, the required performance can always be stably exhibited.

Here, the preferred phosphor particles (II) in the second invention will be illustrated more specifically below. That is, preferred phosphor particles (II) are (c) base phosphor particles having an average particle size of 20 to 40 μm and having a standard deviation of particle size distribution of ± 20% or less of the average particle size, such as zinc sulfide particles, Fluorine-based polymer is monomer composition (mol%) 0 to 50/20 to 80
It is composed of a tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer of 10/10 to 25, and the ultraviolet absorber particles have a particle size of 0.
1 to 1% by weight of particles of zinc oxide or the like, and the film thickness of the fluorine-based mixed coating layer or the fluorine-based coating layer is 0.3 to 2 μm.
m is an average particle diameter of 20 to 44 μm.

Use of Phosphor Particles Phosphor particles (I) and phosphor particles (II) of the present invention are
It is particularly useful as phosphor particles for EL elements, and is extremely useful in, for example, fluorescent display devices used outdoors such as traffic signs and vehicle emergency stop plates, backlights of liquid crystal display devices, fluorescent display devices for various devices, and the like. It can be used preferably. Next, a method for producing an EL device, which is one of the main uses of the phosphor particles (I) and the phosphor particles (II) of the present invention, will be specifically described. That is, for example, barium titanate,
A paste is prepared by dispersing it in a binder such as cyanoethyl cellulose, and the paste is printed on the plane electrode surface of copper, aluminum or the like by screen printing or the like to form a reflective insulating layer. A paste obtained by dispersing phosphor particles (I) or phosphor particles (II) in a binder such as cyanoethyl cellulose is printed on the reflective insulating layer by screen printing or the like to form a light emitting layer, and A transparent electrode is formed on top. As the transparent electrode, for example, a transparent electrode thin film made of indium oxide, tin oxide, antimony oxide or the like, or a laminate of these thin films on the lower surface of a transparent film made of polyester or the like is used. After that, the EL element is obtained by attaching a terminal to each electrode. The EL element may be covered with a water-collecting transparent film, a moisture-proof transparent film, or the like. The dry coating method (I) and the dry coating method (II) used for the production of the phosphor particles (I) and the phosphor particles (II) of the present invention are waterproof, water repellent, light resistant, and oxygen shielded. It can also be applied to coating on other particles for which properties and the like are desired. Examples of such other particles include conductive particles, magnetic particles, electronic materials such as spacers for liquid crystal displays, catalyst carriers, and the like.
Examples thereof include column fillers, carriers for developers, carriers for diagnostic agents, carriers for cell culture, and granular additives for paints, resins, rubbers and the like.

[0016]

EXAMPLES Next, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. Example 1 With an average particle size of 35 μm, the standard deviation of the particle size distribution is ± of the average particle size.
100 g of phosphor particles made of 20% zinc sulfide (doped with cuprous chloride), and an average particle size of 0.5 μ
A tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer having a standard deviation of the particle size distribution of ± 15% of the average particle size in m (mol% = 30/50/20,
5 g of fine powder having a molecular weight of about 70,000) was mixed for 3 minutes with an OM diizer of a hybridization system manufactured by Nara Machinery Co., Ltd. to form an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer of the hybridization system to bond and bond the copolymer fine particles to the surface of the phosphor particles, and then the mixing treatment is continued for another 15 minutes. The surface was smoothed to obtain phosphor particles (I).
This particle is called a phosphor particle (Ia). The phosphor particles (Ia) are
By melting and integrating the copolymer fine particles,
The surface of the phosphor particles was uniformly and smoothly covered with the fluorine-based coating layer, and the average particle diameter was about 37 μm. The particle size distribution of the phosphor particles (Ia) was not different from that of the phosphor particles before the mixing treatment. Obtained phosphor particles (Ia)
An EL device was manufactured using the above, and was kept for 300 hours under the heat and humidity condition of 60 ° C. and relative humidity of 90%. Then 100V,
When the luminance was measured by emitting 120% light at 400 Hz for 50 hours, it was 50% of the phosphor particles (Ia) before the wet heat treatment,
The luminance retention of the untreated phosphor particles measured under the same conditions was significantly improved compared to 10%, and the phosphor particles (Ia)
Had excellent moisture and water resistance. Also, phosphor particles
An EL device was produced using (Ia) and left outdoors for light emission, but no blackening phenomenon was observed even after 12 months.

Example 2 With a mean particle size of 35 μm, the standard deviation of the particle size distribution is ± of the mean particle size.
100 g of phosphor particles consisting of 20% zinc sulfide particles (doped with cuprous chloride), average particle size 0.5 μm
And 2 g of tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer (mol% = 30/50/20, molecular weight of about 70,000) having a standard deviation of the particle size distribution of ± 15% of the average particle size, and 1 g of fine powder of hydrogen sulfide absorbent (RP manufactured by Mitsubishi Gas Chemical Co., Inc.) having an average particle size of 2 μm and a standard deviation of the particle size distribution of ± 25% of the average particle size,
The mixture was mixed for 5 minutes with an OM diizer of a hybridization system manufactured by Nara Machinery Co., Ltd. to form an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer of the hybridization system to bond and bond the respective fine particles to the surface of the phosphor particles, and then 15
The mixing treatment was continued for a minute to smooth the surface to obtain phosphor particles having a fluorine-based preliminary coating layer containing hydrogen sulfide absorbent fine particles. After that, 3 g of the copolymer fine powder was further added, and the mixture was mixed with the OM diizer for 5 minutes,
Formed an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer to bond and bond the copolymer fine particles on the fluorine-based precoat layer, and then the mixing treatment is continued for another 15 minutes to continue the surface treatment. Were smoothed to obtain phosphor particles (I). These particles are called phosphor particles (Ib). Phosphor particles (Ib)
Indicates that the surface of the fluorine-based preliminary coating layer is uniformly and smoothly covered with the fluorine-based coating layer by melting and integrating the copolymer fine particles, and the average particle diameter thereof is about 3
It was 7 μm. The particle size distribution of the coated phosphor particles (Ib) was not different from that of the phosphor particles before the mixing treatment. The brightness of the obtained phosphor particles (Ib) after the wet heat treatment measured in the same manner as in Example 1 is as follows.
Which is 65%, and the brightness retention rate of untreated phosphor particles is 10%
In contrast, the phosphor particles (Ib) had excellent moisture resistance and water resistance. When the phosphor particles (Ib) were left outdoors, no blackening phenomenon was observed even after 12 months.

Example 3 100 g of the phosphor particles (Ia) obtained in Example 1 and an average particle size of 1
1g of 5nm titanium oxide (ultraviolet absorber) fine powder,
The mixture was mixed for 1 minute with an OM diizer of a hybridization system manufactured by Nara Machinery Co., Ltd. to form an ordered mix char. This ordered mixture was mixed for 5 minutes by the hybridizer of the above-mentioned hybridization system, and the titanium oxide fine particles were attached to and bonded to the surface of the phosphor particles (Ia) to obtain phosphor particles (II). . These particles are called phosphor particles (IIa).
The phosphor particles (IIa) were those in which the surface of the fluorine-based coating layer of the phosphor particles (Ia) was uniformly covered with a coating layer composed of titanium oxide fine particles, and the average particle diameter was about 37 μm. The particle size distribution of the phosphor particles (IIa) was the same as that of the phosphor particles (Ia) before the mixing treatment, and had a narrow particle size distribution. Regarding the obtained phosphor particles (IIa), the brightness after the wet heat treatment measured in the same manner as in Example 1 was 60% of that of the phosphor particles (Ia) before the wet heat treatment, and the brightness of the untreated phosphor particles was Retention rate is significantly improved with respect to 10%, and phosphor particles
(IIa) had excellent moisture resistance and water resistance. When the phosphor particles (IIa) were left outdoors, no blackening phenomenon was observed even after 12 months.

Example 4 Instead of the phosphor particles (Ia), the phosphor particles obtained in Example 2
Phosphor particles (II) were obtained in the same manner as in Example 3 except that (Ib) was used. These particles are called phosphor particles (IIb). The phosphor particles (IIb) were those in which the surface of the fluorine-based coating layer of the phosphor particles (Ib) was uniformly covered with a coating layer made of titanium oxide fine particles, and the average particle size was about 37 μm. The particle size distribution of the phosphor particles (IIb) was not different from that of the phosphor particles (Ib) before the mixing treatment. Obtained phosphor particles (II
Regarding b), the luminance after the wet heat treatment measured in the same manner as in Example 1 was 70% of that of the phosphor particles (Ib) before the wet heat treatment, and the luminance retention ratio of the untreated phosphor particles was 10%. It was remarkably improved, and the phosphor particles (IIb) had excellent moisture resistance and water resistance. When the phosphor particles (IIb) were left outdoors, no blackening phenomenon was observed even after 12 months.

[0020]

EFFECTS OF THE INVENTION The phosphor particles (I) of the present invention are extremely excellent in moisture resistance and water resistance, and also excellent in light resistance. Further, the phosphor particles (II) of the present invention are extremely excellent in humidity resistance, water resistance and light resistance. Is excellent. Moreover, in these phosphor particles, each coating layer is firmly fixed, and chemical resistance, solvent resistance, oxygen barrier property, heat resistance and the like are also good. Therefore,
The phosphor particles (I) and the phosphor particles (II) of the present invention are
In particular, it can be used very suitably as phosphor particles for EL devices.

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[Procedure amendment]

[Submission date] December 9, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

EXAMPLES Next, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. Example 1 With an average particle size of 35 μm, the standard deviation of the particle size distribution is ± of the average particle size.
100 g of phosphor particles made of 20% zinc sulfide (doped with cuprous chloride), and an average particle size of 0.5 μ
A tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer having a standard deviation of the particle size distribution of ± 15% of the average particle size in m (mol% = 30/50/20,
5 g of fine powder having a molecular weight of about 70,000) was mixed for 3 minutes with an OM diizer of a hybridization system manufactured by Nara Machinery Co., Ltd. to form an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer of the hybridization system to bond and bond the copolymer fine particles to the surface of the phosphor particles, and then the mixing treatment is continued for another 15 minutes. The surface was smoothed to obtain phosphor particles (I).
These particles are designated as phosphor particles (Ia). Phosphor particles (I
In a), the surface of the phosphor particles is uniformly and smoothly covered with a fluorine-based coating layer by melting and integrating the copolymer fine particles, and the average particle diameter is about 37 μm.
It was m. The particle size distribution of the phosphor particles (Ia) is
It was no different from the phosphor particles before the mixing treatment. An EL device was prepared using the obtained phosphor particles (Ia),
It was kept for 300 hours under a heat and humidity condition of 90% relative humidity. Next, when the luminance was measured by emitting light at 100 V and 400 Hz for 120 hours, the phosphor particles (I
50% of that of a), which is significantly higher than the luminance retention of 10% measured under the same conditions for untreated phosphor particles, and phosphor particles (Ia) have excellent moisture resistance and water resistance. It was Further, an EL device was prepared using the phosphor particles (Ia) and left outdoors to emit light, but no blackening phenomenon was observed even after 12 months.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Example 2 With a mean particle size of 35 μm, the standard deviation of the particle size distribution is ± of the mean particle size.
100 g of phosphor particles consisting of 20% zinc sulfide particles (doped with cuprous chloride), average particle size 0.5 μm
And 2 g of tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene copolymer (mol% = 30/50/20, molecular weight of about 70,000) having a standard deviation of the particle size distribution of ± 15% of the average particle size, and 1 g of fine powder of hydrogen sulfide absorbent (RP manufactured by Mitsubishi Gas Chemical Co., Inc.) having an average particle size of 2 μm and a standard deviation of the particle size distribution of ± 25% of the average particle size,
The mixture was mixed for 5 minutes with an OM diizer of a hybridization system manufactured by Nara Machinery Co., Ltd. to form an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer of the hybridization system to bond and bond the respective fine particles to the surface of the phosphor particles, and then 15
The mixing treatment was continued for a minute to smooth the surface to obtain phosphor particles having a fluorine-based preliminary coating layer containing hydrogen sulfide absorbent fine particles. After that, 3 g of the copolymer fine powder was further added, and the mixture was mixed with the OM diizer for 5 minutes,
Formed an ordered mix char. The ordered mixture is mixed for 10 minutes by the hybridizer to bond and bond the copolymer fine particles on the fluorine-based precoat layer, and then the mixing treatment is continued for another 15 minutes to continue the surface treatment. Were smoothed to obtain phosphor particles (I). These particles are called phosphor particles (Ib). The phosphor particles (Ib) are those in which the surface of the fluorine-based preliminary coating layer is uniformly and smoothly covered with the fluorine-based coating layer by melting and integrating the copolymer fine particles, and the average particle diameter thereof. Was about 37 μm. In addition, coated phosphor particles (I
The particle size distribution of b) was not different from that of the phosphor particles before the mixing treatment. The luminance of the obtained phosphor particles (Ib) after the wet heat treatment measured in the same manner as in Example 1 was 65% of that of the phosphor particles (Ib) before the wet heat treatment, and the luminance of the untreated phosphor particles was Retention rate is significantly improved compared to 10%,
The phosphor particles (Ib) had excellent moisture resistance and water resistance. Also, the phosphor particles (Ib) were left outdoors, but
No blackening phenomenon was observed even after 2 months.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Example 3 100 g of the phosphor particles (Ia) obtained in Example 1 and 1 g of titanium oxide (ultraviolet absorber) fine powder having an average particle size of 15 nm were hybridized by Nara Machinery Co., Ltd. The OM diizer of the system was mixed for 1 minute to form an ordered mix char. The ordered mixture is mixed for 5 minutes by the hybridizer of the hybridization system to bond and bond the titanium oxide fine particles to the surface of the phosphor particles (Ia),
Phosphor particles (II) were obtained. These particles are called phosphor particles (I
Ia). The phosphor particles (IIa) were obtained by uniformly covering the fluorine-based coating layer surface of the phosphor particles (Ia) with a coating layer composed of titanium oxide fine particles, and had an average particle diameter of about 37 μm. In addition, phosphor particles (II
The particle size distribution of a) was the same as the phosphor particles (Ia) before the mixing treatment, and had a narrow particle size distribution. The luminance of the obtained phosphor particles (IIa) after the wet heat treatment, which was measured in the same manner as in Example 1, was as follows.
60% of a), and the brightness retention rate of untreated phosphor particles is 1
It is significantly improved with respect to 0%, and phosphor particles (II
The sample a) had excellent moisture resistance and water resistance. Further, when the phosphor particles (IIa) were left outdoors, no blackening phenomenon was observed even after 12 months.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

Example 4 In the same manner as in Example 3 except that the phosphor particles (Ib) obtained in Example 2 were used instead of the phosphor particles (Ia).
Phosphor particles (II) were obtained. These particles are called phosphor particles (I
Ib). The phosphor particles (IIb) were those in which the surface of the fluorine-based coating layer of the phosphor particles (Ib) was uniformly covered with a coating layer made of titanium oxide fine particles, and the average particle diameter was about 37 μm. Also, phosphor particles (IIb)
The particle size distribution of was the same as that of the phosphor particles (Ib) before the mixing treatment. Regarding the obtained phosphor particles (IIb),
The luminance after the wet heat treatment measured in the same manner as in Example 1 was 70% of that of the phosphor particles (Ib) before the wet heat treatment, which was remarkably improved compared with the luminance retention rate of 10% of the untreated phosphor particles. Therefore, the phosphor particles (IIb) had excellent moisture resistance and water resistance. Further, when the phosphor particles (IIb) were left outdoors, no blackening phenomenon was observed even after 12 months.

Claims (2)

[Claims] 1. Phosphor particles obtained by coating the inorganic dispersion-type phosphor particles with the fluorine-containing vinyl-type polymer by dry-mixing the inorganic dispersion-type phosphor particles and the fluorine-containing vinyl-type polymer particles. 2. The inorganic dispersion-type phosphor particles and the fluorine-containing vinyl-based polymer particles are dry-blended to coat the inorganic dispersion-type phosphor particles with the fluorine-containing vinyl-based polymer, and then the UV-absorber particles are dry-blended. As a result, phosphor particles further coated with an ultraviolet absorber.