JPH04178486A - Production of water-resistant fluophor - Google Patents

Abstract

PURPOSE:To obtain a highly water-resistant fluophor of long working life by coating the surface of a fluophor with a water-resistant inorganic substance followed by rapid heating to melt at least the surface of said substance and then by solidifying said surface. CONSTITUTION:The surface of a fluophor is coated with a water-resistant inorganic substance pref. consisting of Mg and/or Ca phosphate(s) followed by rapid heating to, generally, normal temperatures to ca.90 deg.C (pref. normal temperatures to ca.70 deg.C) and then pref. heat treatment at ca.70-100 deg.C for ca.0.5-3hr to effect melting at least the surface of said coating substance followed by cooling and solidifying said surface, thus obtaining the objective fluophor.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improved method of manufacturing a water-resistant phosphor.

<Prior art> In recent years, copper and/or silver-activated zinc sulfide, copper and manganese-activated sulfide have been used as backlights for display devices due to their characteristics such as uniform brightness over a wide area and light weight. Electroluminescence lamps (hereinafter referred to as EL lamps) using a phosphor mainly made of zinc sulfide, such as zinc or copper-activated zinc sulfide selenide, have been widely used.

However, the phosphor is sensitive to humidity and has the disadvantage that the brightness rapidly decreases due to moisture entering from the outside.

Therefore, conventionally used EL lamps have an insulating layer, a luminescent layer made of a mixture of an organic binder with a high dielectric constant and a phosphor such as zinc sulfide, and a transparent electrode layer disposed on the back electrode. from the outside of the picture electrode to prevent moisture from entering.
It is used as a structure covered with a moisture-proof film,
Even in such a method, if the luminescent layer is exposed to high temperatures for a long time, the surface of the luminescent layer will gradually turn black and deteriorate, resulting in a decrease in brightness.

This tendency is particularly noticeable under ultraviolet irradiation and significantly shortens the life of the EL lamp.

In order to solve these inconveniences, the phosphor is coated with various water-resistant materials to provide water resistance to the phosphor.
An EL lamp with extended life is disclosed.

For example, in Japanese Patent Application Laid-Open No. 58-150294, the phosphor is coated with a dense insulator of silicon nitride, silicon oxide, yttrium oxide, or barium titanate (however, there is no description of the method of coating the insulator), It is taught that by preventing water molecules and various ions from entering the phosphor, the lifetime of the phosphor powder can be extended.

Furthermore, Japanese Patent Publication No. 60-14054 discloses that an oxide layer of an alkaline earth metal is in contact with the surface of an alkaline earth chalcogenide phosphor, and a water-resistant oxide layer is in contact with the oxide of an alkaline earth metal. It is described that the water resistance and chemical stability of the phosphor can be improved by forming a three-layered phosphor in which the layers are formed in this order. Here, a plasma CVD method is exemplified as a method for manufacturing the outermost water-resistant oxide layer.

Furthermore, U.S. Patent No. 4,181.753 describes a zinc phosphate-coated EL phosphor in which a zinc sulfide-based phosphor for EL luminescent material is heat-treated with phosphoric acid and coated with zinc phosphate. It is stated that it gives you the ability to

Furthermore, Japanese Utility Model Application No. 1/77297 describes that an EL element with improved brightness and lifetime can be obtained by treating a phosphor in a plasma gas containing a fluorine-containing compound as an essential component.

However, even with the improvement method described above, the lifespan required for the product (for example, the brightness of the lit phosphor is 1
No phosphor has been obtained that satisfies the requirement (it takes more than 1,500 hours to reach Qnt).

<Problems to be Solved by the Invention> In view of the above circumstances, the present inventors have developed an EL phosphor with excellent water resistance and a long life, and a long life EL panel with improved water resistance using the same. As a result of intensive studies with the aim of obtaining The present inventors have discovered that a phosphor that fully satisfies the above objectives without impairing the characteristics of the phosphor can be obtained if the phosphor is heated and melted rapidly, and the present invention has been completed.

(Means for Solving Problem R) That is, the present invention covers the surface of the phosphor with a water-resistant inorganic material, and then rapidly heats the coating material to melt and then solidify at least the surface of the coating material. An object of the present invention is to provide a method for producing a water-resistant phosphor.

The present invention will be explained in more detail below.

The phosphor that is the object of the present invention is not particularly limited as long as it is a phosphor used for EL lamps, but usually contains zinc sulfide as a main ingredient, and copper, aluminum, silver, manganese, selenium, bromine, and chlorine. In order to impart water resistance to the surface of these phosphors, the surface of the phosphor is first coated with a water-resistant inorganic material.

Such substances include phosphates and the following inorganic substances other than phosphates.

The phosphates used in the present invention are selected from magnesium, calcium, strontium, barium, zinc, aluminum, chromium, manganese, zirconium, tin, cerium, titanium, iron, disochel, lead, yttrium, europium and dysprosium. These are phosphates made of at least one kind of metal, or composite phosphates or mixed phosphates thereof.

More specifically, magnesium phosphate, calcium phosphate, strontium phosphate, barium phosphate, magnesium pyrophosphate, calcium birophosphate, strontium pyrophosphate, barium pyrophosphate, calcium magnesium phosphate, strontium magnesium phosphate, barium magnesium phosphate, pyrroline. Magnesium calcium phosphate, Magnesium strontium pyrophosphate, Magnesium barium pyrophosphate, Magnesium calcium strontium phosphate, Magnesium calcium barium phosphate, Magnesium calcium strontium pyrophosphate, Magnesium calcium barium pyrophosphate,
Magnesium calcium strontium barium phosphate, magnesium calcium pyrophosphate barium strontium, calcium strontium phosphate, calcium barium phosphate, calcium strontium pyrophosphate, calcium barium birophosphate, calcium strontium barium phosphate, calcium strontium barium pyrophosphate, aluminum phosphate, zinc phosphate, chromium phosphate, phosphorus Cobalt acid, cerium phosphate, iron phosphate, lead phosphate, nickel phosphate, manganese phosphate, yttrium phosphate, europium phosphate, dysprosium phosphate, zirconium phosphate, several groups of phosphorus, and titanium phosphate, Magnesium zinc phosphate, magnesium aluminum phosphate, magnesium chromium phosphate, magnesium zirconium phosphate, magnesium tin phosphate, magnesium cerium phosphate, magnesium titanium phosphate, magnesium iron phosphate, magnesium nickel phosphate, magnesium lead phosphate, Magnesium manganese phosphate, magnesium zinc pyrophosphate, magnesium aluminum pyrophosphate, magnesium chromium pyrophosphate, magnesium zirconium pyrophosphate, magnesium tin pyrophosphate, magnesium cerium pyrophosphate, magnesium titanium pyrophosphate, magnesium iron birophosphate, magnesium nickel pyrophosphate, These are lead birophosphate, magnesium manganese pyrophosphate, or a composite phosphate or mixed phosphate of two or more of these.

Examples of water-resistant inorganic substances other than phosphates include metal oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, yttrium oxide, zinc oxide, and magnesium oxide; magnesium silicate, calcium silicate, and strontium silicate. alkaline earth silicate salts such as aluminum and barium silicate; lead silicate glass such as lead silicate and lithium silicate; alumina-silica glass; lead phosphate low melting point glass such as lead fluorate glass and ultra lead phosphate glass; aluminium. Aluminates such as acid magnesium salts; polyphosphoric acids,
Inorganic polymers such as polyaluminum oxide, polysilicon oxide, and polytitanium oxide; titanates and zirconium lead titanate (PZT), lanthanium zirconium containing at least one metal selected from magnesium, calcium, strontium, and barium. Lead titanate (
Examples include ferroelectric titanates such as PLZT), which can be used alone or as a composite or mixture.

Among these, phosphates made of magnesium and/or calcium metals exhibit particularly excellent moisture resistance, and ferroelectric titanates such as PZT and PLZT also exhibit brightness improvement effects, so their application is recommended. .

The coating of these water-resistant inorganic substances on the phosphor is generally due to the fact that the particle size of the phosphor used in the EL clamp is not uniform;
Since it has a central particle diameter of about 10 μm to about 70 μm and a particle size distribution, it is difficult to coat each phosphor particle uniformly and cannot be uniquely defined, but usually WC = [(0,007 to 1.5) d/ Ds. ) Wp [where Wc is the weight of the coating (based on the loaded body) (g), d is the density of the coating (g/cd), and Ds. is the average particle size of the phosphor (μ
m), Wp indicates phosphor weight (g). ], preferably Wc = ((0,015-1.2) d/Dsa)
It is sufficient to cover the range of Wp.

Although it cannot be expressed uniquely depending on the amount of coating, for example, if the particle size is within the above range, it is usually about 0.005. um
~ about 1 μm, preferably about 0.01 μm to about 0.8 μm
A coating thickness in the range of is formed.

If the coating amount is less than the above range, the effect of imparting water resistance etc. to the phosphor will be low even after heat treatment (on the other hand, the drought resistance will be improved as the coating amount is increased, but the brightness will be reduced). Since a decrease occurs, treatment within the above range is preferable.

The method of coating the phosphor with such a water-resistant inorganic substance is not particularly limited as long as the surface of the phosphor is coated with the inorganic substance approximately evenly; for example, in the case of phosphates, To do this, a phosphor is dispersed in an aqueous solution containing phosphate ions and alkali metal ions and/or ammonium ions, and then, while adjusting the pH concentration in the aqueous solution to a range of 4 to 10, magnesium, calcium, etc. are added to the aqueous solution. After adding an aqueous solution of a metal salt consisting of at least one metal selected from the following to coat the phosphor with a phosphate, the phosphor is filtered from the aqueous solution, washed with water, dried, and fired, as necessary. A method of lightly crushing or adding an aqueous solution containing phosphate ions and an aqueous solution of a metal salt made of at least one metal selected from magnesium, calcium, etc. After adding the slurry while adjusting the temperature to a range of 4 to IO, and then heating it, the phosphor is filtered from the slurry, washed with water, dried,
Examples include a method of firing and, if necessary, lightly crushing.

A method for coating these phosphors with phosphate is disclosed in Japanese Patent Application Laid-Open No. 01-01-
It is also detailed in No. 315485.

As a coating method for water-resistant inorganic substances other than the above-mentioned phosphates, a solution in which the metal used for coating is dissolved is added to a slurry solution in which phosphor particles are dispersed, as in the case of coating the above-mentioned phosphates. A metal compound such as an oxide or hydroxide is coated on the phosphor by the so-called hydrolysis method, in which an acid or alkaline solution is added, or the Towa precipitation method, and if necessary, it is added for a while to form a uniform coating layer. After the temperature treatment, the phosphor is filtered from the slurry, dried, and then heated at a temperature that does not cause a 1 degree drop in the phosphor, usually about 600°C or less.
Generally about 50℃ to about 350℃, about 0.5 hours to about 2
An example is a method in which the material is baked for a period of time and then lightly crushed if necessary.

Other methods include a so-called spray coating method in which phosphor particles and a coating material are simultaneously blown into a high-temperature atmosphere, a method in which the phosphor is immersed in a solution raw material, filtered, and dried, and a method in which the phosphor is transferred with the powder used for coating. Examples include a method of coating the surface of the phosphor with a thin layer of powder, and a method of supplying the phosphor and liquid coating raw material into a container and coating the raw material by vaporizing water or solvent while heating and stirring the mixture. It will be done.

When coating, it is preferable to use a method that prevents as much as possible the formation of agglomerated particles in which the coating applied to each phosphor particle contacts and firmly adheres to adjacent phosphor particles before drying and solidification. Strongly fixed agglomerated particles may cause cracking or peeling of the coating layer during crushing treatment, and as a result, it is difficult to obtain a significant waterproofing effect even with rapid heating treatment.

From this point of view, a method in which a desired coating layer is formed on the surface of the phosphor by hydrolysis or neutralization precipitation of the phosphor uniformly dispersed in a liquid is recommended because the resulting coated phosphor is less prone to agglomeration and sticking. be done.

In carrying out the present invention, the phosphate ion-containing aqueous solution includes tripotassium phosphate, dipotassium phosphate, potassium phosphate,
Aqueous alkaline phosphate solutions such as trisodium phosphate, disodium phosphate, and sodium phosphate; ammonium phosphate salts such as triammonium phosphate, niummonium phosphate, and ammonium phosphate; magnesium phosphate, phosphoric acid, and the like are used.

The phosphate ion concentration in the phosphate ion-containing aqueous solution is not particularly limited, but is usually H or PO.

Approximately 0. 1% to about 5% by weight O, preferably about 0
．． It may be used in a range of 0.3% to about 1% by weight.

In addition, raw metal salts include water-soluble chlorides, nitrates, or magnesium sulfate of magnesium, calcium, strontium, barium, zinc, aluminum, chromium, zirconium, tin, cerium, titanium, iron, nickel, lead, and manganese. Inorganic acid salts or water-soluble organic acid salts such as acetates of the above metals, more specifically, magnesium chloride, calcium chloride, strontium chloride,
Chlorides such as barium chloride, zinc chloride, aluminum chloride, chromium chloride, zirconium chloride, tin chloride, cerium chloride, titanium chloride, iron chloride, nickel chloride, lead chloride, manganese chloride, magnesium nitrate, calcium nitrate, strontium nitrate, nitric acid Barium, zinc nitrate, aluminum nitrate, chromium nitrate, zirconium nitrate, nitrate, cerium nitrate, titanium nitrate, iron nitrate, nickel nitrate, lead nitrate,
Nitrates such as manganese nitrate, sulfates such as magnesium sulfate, titanyl sulfate, magnesium acetate, calcium acetate,
Strontium acetate, barium acetate, zinc acetate, aluminum acetate, chromium acetate, cerium acetate, nickel acetate, lead acetate, manganese acetate, polyaluminum chloride, polysilicon oxide (Rudsox H3-4) for other inorganic materials
0/manufactured by DuPont), alkyl metals, organic metals such as silanols, or acetates suitable for these precursors.

It is also optional to use an inorganic acid salt and an organic acid salt in combination.

The metal salt concentration in the raw metal salt solution is approximately 0.01% by weight ~
About IO weight % may be used, preferably about 0.05 weight % to about 5 weight %.

The amount of the phosphate ion-containing aqueous solution or raw metal salt solution to be added to the slurry may be determined as appropriate, taking into consideration the amount of coating on the phosphor, the type and/or the composition.

Normally, when these solutions are added to the slurry, they react immediately, and almost the entire amount of the added amount is deposited as a metal compound such as phosphate on the phosphor dispersed in the slurry. However, according to a simple preliminary experiment, The amount of the phosphate ion-containing aqueous solution or the raw metal salt solution to be added may be determined on a lit basis.

The reaction temperature is not particularly limited, but is usually room temperature to about 90°C.
, preferably at room temperature to about 70'C.

In addition, the reaction ends almost instantaneously when the phosphate ion-containing aqueous solution and the raw metal salt aqueous solution, or the raw metal salt aqueous solution comes into contact with the acid or alkaline solution, but the reaction-completed solution is
Subsequently, it is recommended to heat the material to about 0° C. to about 100° C. for about 0.5 hours to about 3 hours.

This heating treatment completes the coating of the phosphor with metal compounds such as phosphates generated by the reaction, and at the same time, aging treatment is also carried out, so that the coated material becomes smoother and more uniform in the phosphor. It has a covering effect.

The coated phosphor slurry thus obtained after the heating treatment is cooled while maintaining the dispersion of all particles, filtered according to a conventional method, and the phosphor is fractionated, and then washed with water and kept at room temperature. ~about 15
Dry and bake at 0° C. by a known method such as air drying, hot air drying, or vacuum drying.

The temperature at which the coating is fired in advance during the rapid heating described above is set so as not to reduce the brightness of the phosphor substrate and to remove volatile substances such as water, solvents, or binders that adhere to the coating. , usually below about 600°C, preferably about 50°C
What is necessary is just to bake in the temperature range of 0.degree. C. to about 350.degree. C. for about 0.5 hours to about 2 hours.

Further, when the coating treatment is performed in multiple steps, it is possible to obtain a denser coating with fewer defects, and the moisture resistance can be further improved.

Next, in the present invention, in order to further improve the water resistance of the obtained phosphor particles having an inorganic substance coating, they are rapidly heated to melt and solidify at least the surface of the coating.

Such treatment closes the pores and cracks in the film and significantly improves the water resistance.

The rapid heating method is not particularly limited as long as the coated phosphor is supplied into a high-temperature atmosphere and at least the coating surface of the phosphor can be melted, but plasma treatment is performed in nine cases.

The plasma treatment of the present invention is a treatment method capable of melting and solidifying at least the surface of the coating material and converting it into an integrated coating without cracks or bores without degrading the physical properties of the phosphor that is the base material. Specifically, the treatment is selected from low pressure plasma treatment, normal pressure plasma treatment, high pressure plasma treatment, etc., and the coated surface is melted and solidified by instantaneous heating for several seconds or less, usually one second or less. This plasma treatment is recommended because the brightness of the obtained phosphor is less reduced.

The plasma equipment to be used and its working conditions are not unambiguous as they largely depend on the melting point of the coating material used for plasma treatment, but for example, a phosphor coated with phosphate is placed in a conical container with argon, nitrogen, helium, etc. While forming a fluidized bed with an inert gas or a gas flow of hydrogen mixed with the inert gas and the coated phosphor, the phosphor coated with a metal oxide with a high melting point can be treated with a plasma spray gun. It is also possible to process the coated phosphor by flowing it into a gas flow such as inert gas generated. In any case, when performing plasma treatment, it is recommended to select treatment conditions suitable for the coating material through simple experiments.

The plasma-treated phosphor particles may be used as a normal phosphor as is, or after being lightly crushed if necessary.

That is, the surface of the phosphor is coated with an inorganic substance between the back electrode layer and the transparent electrode layer, and then the coating is rapidly heated to melt at least the surface of the coating material and then solidified to emit light. By disposing it as a body layer, it is possible to provide an EL lamp with excellent water resistance.

When coating with the water-resistant inorganic substance of the present invention, it is of course possible to appropriately coat with a coloring dye or an organic and/or inorganic ultraviolet absorbing material within an amount that does not impair moisture resistance. be. In addition, the coating with the water-resistant inorganic material may be a single layer coating, or may be a multilayer coating, regardless of whether the same type of coating layer or different types of coating layers are used, as long as the reduction in brightness does not impair practicality. It is not clear why the method of the present invention is able to produce a phosphor with excellent water resistance compared to a method in which a ceramic material is directly applied to a phosphor using a plasma CVD method or the like to impart water resistance, but Because it takes time to uniformly coat the ceramic material, it is assumed that inter-particle adhesion occurs during this time, resulting in cracking and peeling of the coating during crushing, making it impossible to exhibit sufficient water resistance. be done.

<Effects of the Invention> As detailed above, the phosphor obtained by the method of the present invention can provide better water resistance than the phosphor obtained by conventionally known coating methods. Of course, it can be used for organic dispersion type EL lamps having a conventionally known moisture barrier layer.
This makes it possible to provide an organic dispersion type EL lamp that does not require a moisture barrier layer and is simply mixed with a dielectric resin and disposed between the back electrode layer and the transparent electrode layer, and can be used as a long-life EL panel, for example, in bank lights for word processors, and in aircraft. It can be applied to all kinds of applications as panel lights, such as panel lights for automobiles, interior panel lights for automobiles, weather-resistant exterior panel lights for automobiles, and panel lights for ships, and its industrial value is extremely large.

<Example> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the Examples are for explaining one embodiment of the present invention, and the present invention is not limited thereby.

The life test and blackening resistance test used in Examples and Comparative Examples were conducted by the following method.

Lifespan test: An unencapsulated EL light emitter (experimental EL lamp described below) was continuously lit in a constant temperature chamber at a temperature of 25°C and a humidity of 60% RH at 115cm, 400H2 drive, and its initial brightness (nt) Then, the lifetime until the initial brightness decreased to half the brightness (half life (hr)) was measured. (Table 1) Humidity test: After holding the EL light emitting body in a constant temperature and constant temperature chamber at a temperature of 65°C and a humidity of 95% RH for 100 hours, it was placed in a constant temperature and constant temperature chamber at a temperature of 23°C and a humidity of 40 to 60% RH at 115V. , 400H2 drive, and the initial brightness (nt), half life (hr), and 10nt life (hr) (time until the brightness reaches 1Qnt) were measured. (Table 1) Darkening resistance test: EL phosphor sample 0.200g, castor oil 0
．． 100 g and 13 μl of a 23 volume % water-ethanol solution were kneaded, and the luminance after emitting light for 30 minutes at 200 V and 400 Hz in a 50 μm thick light emitting cell was shown as the brightness maintenance rate [%] with respect to the initial brightness. (Table 1) Darkening resistance test: 0.200 g of an EL phosphor sample, 0.100 g of castor oil, and 13 μl of a 23% by volume water-ethanol solution were kneaded, and the mixture was heated using an ultraviolet lamp UL ■ in a 50 μm thick light emitting cell. After emitting light for 30 minutes under -56 irradiation, 200■, 400H2 drive, the blackening change of the fluorescent-absent children was examined, and those that darkened were marked as ×, and those that did not darken were marked as ○ (Table 1) In addition, parts in Examples indicate parts by weight.

Example 1 In a full flask, 200 g of deionized water and 100 g of a commercially available zinc sulfide EL phosphor (average particle size 30 μm) were added.
φ) was heated to 70°C and stirred using a paddle stirring blade. Into the phosphor-dispersed slurry, 0.71 g of triammonium phosphate trihydrate was dissolved in deionized water to add 60-phosphoric acid. A metal salt aqueous solution prepared by dissolving triammonium aqueous solution, 0.53 g of magnesium chloride hexahydrate, and 0.38 g of calcium chloride dihydrate in deionized water was added to the slurry at an addition rate of 0.5 d/min. The slurry was added over 2 hours while drastically adjusting the pH to a range of 6 to 8 (by adding an aqueous sodium hydroxide solution), and then the slurry temperature was adjusted to about 0°C to 8°C.
After heating to about 100°C and holding for 1 hour with continuous stirring,
Cooled to room temperature.

After solid-liquid separation, the obtained phosphate-coated EL phosphor was washed with deionized water, dried at a temperature of 130°C for 1 hour, crushed, and further heated in an electric furnace at a temperature of 150°C for 1 hour, then at a temperature of 300°C. Baked for 1 hour, coated with magnesium calcium phosphate (0,4
5% by weight---(weight part of phosphate coating/phosphor 10
0 parts by weight) x 100) EL phosphor was obtained.

The EL phosphor thus obtained was coated again by the above method, and the coating was carried out twice in total. I got it.

Next, plasma blasting equipment W (6MM-630 manufactured by Metco)
Argon plasma jet flame (arc current 14 OA
), and was subjected to plasma treatment to obtain a phosphor whose phosphate-coated surface was melted and solidified.

Then, B a was deposited on the aluminum thin plate as the back electrode.
An insulating layer made of T i Os and a high dielectric constant cellulose resin composition was formed, and 15 parts of a high dielectric constant cellulose resin (dielectric constant 1B) and 45 parts of dimethylformamide were added on top of the insulating layer, which was then subjected to plasma treatment. 40 parts of magnesium calcium phosphate coated phosphor were mixed, coated using a doctor blade method, and then heated and dried at 130°C for 10 minutes.
A phosphor layer with a thickness of 50 μm is formed, a TTO transparent electrode is formed on it, and an experimental EL lamp (covered with a moisture-proof polychlorotrifluoroethylene film) is used.
It is called L lamp. ) was produced.

A life test of the unencapsulated EL lamp produced as described above and a blackening resistance test of the plasma-treated phosphate-coated phosphor were conducted.

The results are shown in Table 1.

Comparative Example 1 Using the same commercially available zinc sulfide-based EL phosphor used in Example 1 (without coating treatment), an unencapsulated EL lamp was prepared in the same manner as in Example 1, and subjected to a life test and an unencapsulated EL lamp. The blackening resistance test of the coated phosphor was conducted.

The results are shown in Table 1.

Example 2 A fired phosphate-coated phosphor obtained in the same manner as in Example 1 (
100 g of non-plasma treated) was added to an isopropanol solution 50-1 in which 0.24 g of titanium tetraisopropoxide (A-1/manufactured by Nippon Soda) and 0.22 g of barium diisopropoxide were dissolved, and the mixture was heated in a rotary evaporator. While stirring, the solvent was distilled off to dryness.

After drying this material at a temperature of 130°C for 1 hour and crushing it,
It was fired in an electric furnace at a temperature of 150°C for 1 hour and then at 300°C for 1 hour.

Furthermore, barium titanate (approximately 0.2% by weight)/phosphate (approximately 0.9% by weight) was plasma-treated at a higher temperature by replacing the argon plasma jet flame with an argon-hydrogen jet flame in the plasma treatment of Example 1. ) A multilayer coated phosphor was obtained.

Next, an unencapsulated EL lamp was manufactured in the same manner as in Example 1.

A life test of the unencapsulated EL lamp produced as described above and a blackening resistance test of the plasma-treated barium titanate multilayer coated phosphor were conducted.

The results are shown in Table 1.

Comparative Example 2 Using the phosphate-coated phosphor (not plasma-treated) obtained in Example 1, an unencapsulated EL lamp was manufactured in the same manner as in Example 1, and a life test and evaluation of the phosphate-coated phosphor Blackening resistance tests were conducted.

The results are shown in Table 1.

Comparative Example 3 An unencapsulated EL lamp was manufactured in the same manner as in Example 1 using the phosphate-barium tannate multilayer coated phosphor (not plasma treated) obtained in Example 2, and its lifespan was In addition, a blackening resistance test of the barium titanate coated phosphor was conducted.

The results are shown in Table 1.

Example 3 A fired phosphate-coated phosphor obtained in the same manner as in Example 1 (
100 g of non-plasma treated) was mixed with low melting point glass powder (lead tin fluorophosphate: 5n-Pb-F-P-0, quantity ratio (mol%) 2
0; 2; 13; 18; 47, glass transition temperature 125°C,
It was placed in a grooved 200* eggplant-shaped flask together with 0.2 g of particles having a particle size of approximately 3 μmφ, and the mixture was rotated and stirred for 1 hour using a rotary evaporator drive.

Next, the flask was heated in a Matsufuru furnace for 30 minutes while rotating.
After heating and melting at 0° C. for 0.5 hours, and then at 350° C. for 0° 5 hours, the mixture was allowed to stand still and slowly cooled, and then cooled to room temperature over 8 hours.

This product was subjected to plasma treatment in the same manner as in Example 1 to obtain a multilayer phosphor coated with fluorophosphate (approximately 0.2% by weight) and phosphate (0.9% by weight).

Next, an unencapsulated EL lamp was manufactured in the same manner as in Example 1.

A life test of the unencapsulated EL lamp produced as described above and a blackening resistance test of the ceramic composite phosphate coated phosphor were conducted.

The results are shown in Table 1.

Example 4 A fired phosphate-coated phosphor obtained in the same manner as in Example 1 (
In Example 1, 100 g of triammonium phosphate trihydrate (non-plasma treated) was added to polysilicon oxide (Ludox H
A silica-coated phosphor was prepared in exactly the same manner except that magnesium chloride and calcium chloride raw materials were dissolved and diluted in 0.50 g of 3-40/manufactured by DuPont Co., Ltd. in place of 4X 10-3 M/L phosphoric acid aqueous solution 18-4. Obtained.

Subsequently, plasma treatment was performed in the same manner as in Example 1 to obtain a silica (approximately 0.2% by weight)/phosphate (approximately 0.9% by weight) multilayer coated phosphor.

Next, an unencapsulated EL lamp was manufactured in the same manner as in Example 1.

A life test of the unencapsulated EL lamp produced as described above and a blackening resistance test of the plasma-treated silica multilayer coated phosphor were conducted.

The results are shown in Table 1.

Comparative Example 4 Using the phosphor silica multilayer coated phosphor (not plasma treated) obtained in Example 4, unencapsulated E was prepared in the same manner as in Example 1.
An L lamp was manufactured, and a life test and a blackening resistance test of the coated phosphor were conducted.

The results are shown in Table 1.

Example 5 In Example 1, 0.41 g of titanium tetrachloride was used instead of triammonium phosphate trihydrate, magnesium chloride hexahydrate, and calcium chloride dihydrate.

An aqueous solution made by dissolving 0.52 g of barium chloride dihydrate and 11
A phosphor coated with barium titanate was obtained in exactly the same manner except that the aqueous solution was used instead.

Subsequently, plasma treatment was performed using the same argon-hydrogen plasma jet flame as in Example 2 to obtain an EL phosphor coated with barium strontium titanate (coating amount: 0.8% by weight).

Next, an unencapsulated EL lamp was manufactured in the same manner as in Example 1, and a life test and a blackening resistance test of the plasma-treated barium strontium titanate coated phosphor were conducted.

The results are shown in Table 1.

Comparative Example 5 Using the barium strontium titanate coated phosphor (not plasma treated) obtained in Example 5, an unencapsulated EL lamp was manufactured in the same manner as in Example 1, and a life test and durability test of the coated phosphor were conducted. Blackening test etc. were conducted.

The results are shown in Table 1.

Example 6 The same commercially available zinc sulfide-based EL phosphor 1 used in Example 1
00g and barium titanate) powder (particle size 0.05μm
φ/manufactured by Sumitomo Cemen Co., Ltd.) Ig was immersed in methanol 50TI& in which 0.01 g of polyvinyl alcohol was dissolved, and the solvent was distilled off to dryness while stirring with a rotary evaporator in a grooved 200-shaped eggplant flask.

This material was dried and crushed at 130° C. for 1 hour in the same manner as in Example 2, and then fired in an electric furnace at 150° C. for 1 hour and then at 300° C. for 1 hour.

Subsequently, plasma treatment was performed using the same argon-hydrogen plasma jet flame as in Example 2 to obtain an EL phosphor coated with barium titanate (coating amount: 1% by weight).

Next, an unencapsulated EL lamp was manufactured in the same manner as in Example 1, and a life test and a blackening resistance test of the plasma-treated barium titanate-coated phosphor were conducted.

The results are shown in Table 1.

Comparative Example 6 Using the barium titanate coated phosphor obtained in Example 6 (non-plasma treated), unencapsulated E was prepared in the same manner as in Example 1.
An L lamp was manufactured and a life test and a blackening resistance test of the coated phosphor were conducted.

The results are shown in Table 1.

Claims (1)

[Scope of Claims] 1) Water-resistant fluorescent material characterized by coating the surface of the phosphor with a water-resistant inorganic substance, then rapidly heating the coating material to melt at least the surface of the coating material and then solidifying it. How the body is manufactured. 2) The water-resistant inorganic substance that coats the surface of the phosphor is magnesium, calcium, strontium, barium, zinc, aluminum, chromium, manganese, zirconium, tin, cerium, titanium, iron, nickel, lead, yttrium, europium, and dysprosium. 2. The method for producing a water-resistant phosphor according to claim 1, wherein the phosphor is at least one of a phosphate made of at least one kind of metal, a composite phosphate, or a mixed phosphate thereof. 3) Water-resistant inorganic substances that coat the surface of the phosphor include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide,
2. The method for producing a water-resistant phosphor according to claim 1, wherein the material is at least one metal oxide such as yttrium oxide, zinc oxide, and zirconium oxide. 4) The water-resistant inorganic material that coats the surface of the phosphor is magnesium silicate,
2. The method for producing a water-resistant phosphor according to claim 1, wherein the material is at least one alkaline earth silicate salt such as calcium silicate, strontium silicate, and barium silicate. 5) The water resistant material according to claim 1), wherein the water resistant inorganic substance coating the surface of the phosphor is at least one of inorganic polymers such as polyphosphoric acid, polyaluminum chloride, polysilicon oxide, and polytitanium oxide. A method for producing a fluorescent phosphor. 6) The water-resistant inorganic substance coating the surface of the phosphor is at least one of magnesium titanate, calcium titanate, barium titanate, barium strontium titanate, lead zirconium titanate (PZT), and lanthanum zirconium lead titanate (PLZT). 2. The method for producing a water-resistant phosphor according to claim 1, wherein the water-resistant phosphor is one type. 7) The method for producing a water-resistant phosphor according to claim 1, wherein the method for melting at least the surface of the coating material is a plasma treatment method. 8) Claim 1, wherein the phosphor is a zinc sulfide-based EL phosphor.
) A method for producing a water-resistant phosphor as described above.