JP3327963B2 - Method for producing blue light-emitting phosphor with pigment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pigmented blue light-emitting phosphor suitable for a fluorescent film such as a color cathode ray tube.

[0002]

2. Description of the Related Art In order to improve the contrast of an image such as a color cathode ray tube or a fluorescent display tube, it is known to attach a filter material for absorbing reflection of external light on a phosphor screen to a phosphor surface. In addition, a filter material may be attached to the phosphor surface in order to sharpen the emission spectrum of the phosphor. The pigmented blue light-emitting phosphor is
Usually, a cobalt blue pigment (a pigment containing cobalt aluminate as a main component) or a cobalt-zinc-silicon pigment (see Japanese Patent Application No. 3-148636) having a particle size of about 0.1 to 0.7 μm is used as a binder ( (SBR, gelatin, acrylic polymer, etc.) adheres to the phosphor surface. However, the method of attaching a pigment using a binder has a problem in that the pigments are aggregated at the time of attachment to deteriorate the characteristics of the fluorescent film. In addition, in recent years, there has been a demand for an improvement in contrast, and it is necessary to increase the amount of pigment attached by about five times as compared with the conventional method. However, there is also a problem that the pigment once adhered is peeled off when the pigment is applied to a cathode ray tube.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, suppresses the aggregation of the pigment at the time of adhering the pigment to the fluorescent substance, and is capable of adhering a large amount of the pigment with a strong adhesive force. An object of the present invention is to provide a method for manufacturing a light emitting phosphor.

[0004]

The present invention is the following method for producing a pigmented blue light-emitting phosphor. In the method for producing a pigmented blue light-emitting phosphor, an aqueous solution or aqueous dispersion containing cobalt and zinc, an aqueous solution or aqueous dispersion containing silicon, a dispersion of a blue light-emitting phosphor, and a pH adjuster or a precipitant. Mixing to form a co-precipitate of cobalt, zinc and silicon, filtering and washing the mixture of the co-precipitate and the blue light-emitting phosphor, washing with water, drying and calcining; A method for producing a phosphor.

In a method for producing a pigmented blue light-emitting phosphor, an aqueous solution or dispersion containing cobalt and zinc is provided.
An aqueous solution or dispersion containing silicon, a dispersion of a blue light-emitting phosphor, and urea are mixed, and the mixed slurry is heated to produce a coprecipitate of cobalt, zinc and silicon, and the coprecipitate and After filtering the mixture with the blue light-emitting phosphor and washing with water,
A method for producing a pigmented blue light-emitting phosphor, which is dried and fired.

In the above-mentioned or the above-mentioned method for producing a pigmented blue light-emitting phosphor, a mixture of the coprecipitate and the blue light-emitting phosphor is subjected to a hydrothermal synthesis treatment, and then filtered, washed with water and dried. A method for producing a pigmented blue light-emitting phosphor.

An alkoxide containing cobalt, zinc and silicon is dissolved in an organic solvent, and a blue light emitting phosphor is added and mixed, and then coprecipitated as a metal oxide by hydrolysis. A method for producing a blue light-emitting phosphor with a pigment, comprising filtering, washing, drying, and firing the mixture.

An organometallic compound containing cobalt, zinc, and silicon is dissolved or slurried in an organic solvent, and a blue light-emitting phosphor is added and mixed. The mixture is heated and pressurized to deposit a metal oxide on the phosphor surface. A method for producing a blue light-emitting phosphor with a pigment, characterized in that the phosphor is filtered, washed, and dried.

[0009]

The present inventors have studied various kinds of blue light-emitting phosphors with pigments. As a result, by adhering a Co-Zn-Si-based blue pigment to the phosphors without using a binder, the aggregation of the pigments at the time of pigment attachment can be reduced. The present invention was found to be able to suppress such a phenomenon, and to improve the adhesion of the pigment to the phosphor, thereby completing the present invention.
The molar ratio of the oxide equivalent of xCoO · yZnO · zSiO ₂ type blue pigment, as used herein, 0.05 ≦ x / z ≦ 1 .
5, 0.1 ≦ y / z ≦ 2.0, especially 0.2 ≦ x / z ≦
1.0, 0.3 ≦ y / z ≦ 1.7 is preferred. Outside of this range, the color tone will change, making it unsuitable for combination with a blue-emitting phosphor.

The first method for producing the pigmented blue light-emitting phosphor of the present invention comprises an aqueous solution or aqueous dispersion containing cobalt and zinc (referred to as liquid I) and an aqueous solution or aqueous dispersion containing silicon (referred to as liquid II). ), A dispersion of a blue light-emitting phosphor, and
A pH adjuster or a precipitant is mixed to form a coprecipitate of cobalt, zinc and silicon, and the mixture of the coprecipitate and the blue light-emitting phosphor is filtered, washed with water, dried and calcined. This is a method for producing a pigmented blue light-emitting phosphor. The above-mentioned coprecipitate is formed by preparing a dispersion of the liquid I, the liquid II, and the blue light-emitting phosphor in advance, mixing them at the same time, and adding a pH adjuster or a precipitant, or After the light emitting phosphor is dispersed in the liquid I or the liquid II, another liquid and a pH adjuster or a precipitant are mixed to obtain a coprecipitate.

Here, cobalt and zinc can be used as aqueous solutions of chlorides, fluorides, sulfates, nitrates and the like, and silicon uses alkali silicates of potassium and sodium in addition to colloidal silica. As the colloidal silica, any commercially available colloidal silica can be used, and in particular, those having a particle diameter in the range of several tens to several hundreds of nm are preferable for operation. pH
As a modifier, caustic soda, sodium carbonate, hydrochloric acid, sulfuric acid, and the like can be used.
It is preferable to adjust to a range of 9.5. If the pH is lower than 7.0, the precipitation of cobalt and zinc becomes insufficient and p
If it exceeds H9.5, the precipitation of silicon may be insufficient. Also, oxalic acid or the like can be used as a precipitant. The firing temperature is preferably in the range of about 500 to 1200 ° C. For drying and firing, an electric furnace, a gas furnace, a steam furnace, a (far) infrared heating furnace, or the like can be used.

In a second method for producing a pigmented blue light-emitting phosphor of the present invention, urea is added instead of the pH adjuster or precipitant of the first method, and the mixed slurry is heated to obtain cobalt, zinc and The difference is that a coprecipitate of silicon is generated, and the other conditions are the same as those in the first manufacturing method, in which a blue light-emitting phosphor with a pigment is manufactured. The heating temperature is preferably in the range of 70 to 100 ° C. The firing conditions are the same as in the first manufacturing method, and the same furnace for drying and firing can be used.

In a third method for producing a pigmented blue light-emitting phosphor of the present invention, instead of firing in the first or second method,
Put the above mixed slurry containing coprecipitate into a pressure vessel and add about 1
This is a method for producing a pigmented blue light-emitting phosphor by performing a hydrothermal reaction in a temperature range of 00 to 1000 ° C, preferably 200 to 500 ° C.

In a fourth method for producing a pigmented blue light-emitting phosphor of the present invention, an alkoxide containing cobalt, zinc and silicon is dissolved in an organic solvent, and the blue light-emitting phosphor is added, mixed and hydrolyzed. A method for producing a pigmented blue light-emitting phosphor characterized by co-precipitating as an oxide, filtering a mixture of the co-precipitate and the blue light-emitting phosphor, washing, drying and calcining, As the solvent, ethanol, methanol and the like can be used, and as alkoxides of cobalt, zinc and silicon, dimethoxy cobalt, diethoxy cobalt, dimethoxy zinc, diethoxy zinc,
Tetramethoxysilicon, tetraethoxysilicon, or the like can be used. At the time of hydrolysis, it is preferable to heat to 30 to 40 ° C. while adding an appropriate amount of aqueous ammonia.
The firing conditions are the same as those in the first manufacturing method, and the same furnace for drying and firing can be used.

According to a fifth method for producing a pigmented blue light emitting phosphor of the present invention, a mixed slurry is prepared by dissolving an organometallic compound containing cobalt, zinc and silicon in an organic solvent and adding the blue light emitting phosphor. After that, put in a pressure vessel for about 100-5
This is a method of producing a pigmented blue light-emitting phosphor by heating and pressurizing at a temperature of 00 ° C, preferably 200 to 400 ° C, and using 1,4 butanediol, toluene, xylene and the like as an organic solvent. As the organometallic compound of cobalt, zinc and silicon, dimethoxycobalt, diethoxycobalt, tetramethoxysilicon, tetraethoxysilicon, zinc acetate and the like can be used.

In the above-mentioned production method, an oxidizing agent may be contained in the aqueous solution or the aqueous dispersion to promote the oxidation reaction and improve the filter characteristics. As the oxidizing agent, hydrogen peroxide, sodium peroxodisulfate and the like can be used. Further, in the above-described production method, instead of the calcination treatment, the filter characteristics may be improved by irradiating the dried blue light-emitting phosphor with pigment with vacuum ultraviolet rays or short-wavelength ultraviolet rays in a vacuum or an inert atmosphere. It is possible. The intensity of vacuum ultraviolet light or short wavelength ultraviolet light is usually 0.5 mW / cm ² or more, and argon, nitrogen, or the like can be used as the inert atmosphere.

On the other hand, in order to improve the adhesion of the pigment to the blue light-emitting phosphor or to inactivate the phosphor substrate, in the above-mentioned manufacturing method, a base coat is previously adhered to the surface of the blue light-emitting phosphor. be able to. As the undercoat, A
Metal oxides or hydroxides such as l, Zn, Si, Ti, Co, and Zr can be used. Various mineralizers and other elements can be contained in the coprecipitation step and / or the calcination step of the above-described production method, if necessary. Specifically, Li, Na, K, Ca, Mg, Ba, Fe, N
i, Cu, Mn, Ti, V, Al, Sn, Sb, Cr,
Pr, B, Mo and the like may be contained. These elements can be added in an amount of about 5% by weight or less in the attached pigment. If it exceeds this, it becomes impossible to obtain a color tone preferable as a blue pigment.

A blue light emitting fluorescent material that can be used in the present invention
The light source has an emission spectrum within the range of 380 to 500 nm.
It has the main parts of
Zinc halide based phosphor [ZnS: Ag, X (X is halogen or
Al), ZnS: Ag, M, X (M is Ga, In, etc., X
Is halogen or Al)], Y_TwoSiO_Five: Ce, Ca _Two
B_FiveO₉Cl: Eu, (Ba_xMg_1-x) OnAl_Two
O_Three: Eu (0 ≦ x ≦ 1; 1.5 ≦ n ≦ 4.5), Sr
Si_ThreeO₈Cl_Four: Eu, CaWO_Four, CaWO_Four: P
b, BaFCl: Eu, Gd_TwoO_TwoS: Tb, ZnS:
Zn and the like can be mentioned. In addition, the above blue pigment
The adhesion amount is in the range of 0.1 to 15% by weight based on the phosphor.
preferable. If the adhesion amount falls below the lower limit, the filter
The effect is too small.
May not be the minute.

[0019]

【Example】

(Example 1) 6.07 parts by weight of cobalt chloride hexahydrate, 3.46 parts by weight of zinc chloride, 1.53 parts by weight of solid content of colloidal silica (ST-20L manufactured by Nissan Chemical Industries, Ltd.), and (Ba)
100 parts by weight of _0.5 Mg _0.5 ) O.3.5 Al ₂ O ₃ : Eu blue light-emitting phosphor was dissolved and slurried in 150 parts by weight of demineralized water. While stirring, a 1N aqueous solution of sodium hydroxide was added little by little to adjust the pH to 8.5 to coprecipitate. Thereafter, the slurry was washed with filtered water and dried at 120 ° C. for 15 hours. Next, the dried mixture was fired at 1000 ° C. for 1 hour to obtain a blue luminescent phosphor with a Co.Zn.Si based pigment.

Example 2 In a separable flask equipped with a condenser, 7.42 parts by weight of cobalt nitrate hexahydrate, 3.46 parts by weight of zinc chloride, and colloidal silica (manufactured by Nissan Chemical Industries, Ltd.)
T-20L) solids 1.53 parts by weight of urea 15.3 parts by weight, _{and, (Ba 0.5 Mg 0.5) O} · 3.5Al 2 O 3:
100 parts by weight of the Eu blue-emitting phosphor is mixed with 150 parts of demineralized water at room temperature.
It was dissolved and slurried in parts by weight. This was heated with stirring and reacted at 90 ° C. for 20 hours. Next, the reaction mixture was filtered, washed with water, dried at 120 ° C. for 15 hours, and further calcined at 1000 ° C. for 1 hour to obtain CoO.ZnO.Si.
A blue light emitting phosphor with an O ₂ -based pigment was obtained.

Example 3 Diethoxy Cobalt 3.80
Parts by weight, 3.94 parts by weight of diethoxy zinc, 5.30 parts by weight of tetraethoxy silicon, and (Ba _0.5 Mg _0.5 ) O
100 parts by weight of 3.5 Al ₂ O ₃ : Eu blue light emitting phosphor was dissolved and slurried in 150 parts by weight of ethanol at room temperature. While stirring, 28% aqueous ammonia solution was added for 2 hours.
0 parts by weight were added, heated to 40 ° C., and reacted for 2 hours.
After completion of the reaction, the mixture was filtered, washed with ethanol, air-dried to remove ethanol, and calcined at 900 ° C. for 2 hours to obtain CoO · Zn.
A blue light emitting phosphor with an O.SiO ₂ pigment was obtained.

(Example 4) In Example 1, (Ba
_0.5 Mg _0.5 ) O.3.5 Al ₂ O ₃ : Co-precipitated in the same manner as in Example 1, except that a blue light emitting phosphor of ZnS: Ag, Cl was used instead of the blue light emitting phosphor. Thereafter, the mixed slurry was hydrothermally reacted at 350 ° C. for 2 hours in an autoclave. After the reaction, the resultant was filtered, washed with water, and dried at 120 ° C. for 15 hours to obtain a blue light-emitting phosphor with a CoO.ZnO.SiO ₂ pigment.

Example 5 Diethoxy cobalt 3.80
Parts by weight, 5.59 parts by weight of zinc acetate dihydrate, 5.30 parts by weight of tetraethoxysilicon, and 100 parts by weight of ZnS: Ag, Cl blue light-emitting phosphor were converted into 150 parts by weight of 1,4-butanediol at room temperature. After dissolving / slurrying and purging this with nitrogen in an autoclave, the mixture was reacted at 300 ° C. for 3 hours. After completion of the reaction, the mixture was filtered, washed with methanol, and air-dried to obtain a CoO.ZnO.SiO ₂ -based pigmented blue light-emitting phosphor.

Example 6 In Example 1, after coprecipitation was formed, 5 parts by weight of sodium peroxodisulfate was added and the mixture was boiled. Then filtered, washed with water and dried in vacuum (10 ^-5
UV (wavelength: 147 nm) (ultraviolet intensity: 8 mW / cm ² ) to obtain CoO.ZnO.SiO ₂
A blue light-emitting phosphor with a system pigment was obtained.

(Example 7) In Example 1, a base film of aluminum hydroxide was previously formed on the phosphor surface using an aqueous solution of sodium aluminate (0.2% in terms of alumina with respect to the phosphor). Thereafter, in the same manner as in Example 1, Co
A blue light emitting phosphor with an O.ZnO.SiO ₂ pigment was obtained.

Example 8 Cobalt chloride hexahydrate 6.0
7 parts by weight and 3.46 parts by weight of zinc chloride are dissolved in 50 parts by weight of demineralized water to obtain liquid I, and 1.53 parts by weight of silica water in terms of silica solid content is dissolved in 10 parts by weight of demineralized water to obtain liquid II. And On the other hand, (Ba _0.5 Mg _0.5 ) O.3.5 Al
100 parts by weight of ₂ O ₃ : Eu blue light emitting phosphor is demineralized water 10
Dispersed in 0 parts by weight to obtain Liquid III. While maintaining the solution III at 30 ° C., the solution I and the solution II are each stirred at a constant speed for 3 hours.
It was added for 0 minutes to coprecipitate. During this time, liquid III was 0.1
Aqueous sodium hydroxide solution or O.N. The pH was adjusted to 8.0 to 8.5 with 1N hydrochloric acid. After completion of the addition, the mixture was aged for 1 hour. Thereafter, the dispersion was filtered and washed with water.
Dry at 0 ° C. for 15 hours. The dry mixture is then added to 10
It was baked at 00 ° C. for 1 hour to obtain a blue luminescent phosphor with a Co.Zn.Si pigment.

Example 9 In Example 8, after aging was completed, 5 parts by weight of sodium peroxodisulfate was added, and
Co · Z in the same manner as in Example 8 except that the mixture was boiled for 0 minutes.
A blue light emitting phosphor with an n-Si pigment was obtained.

Example 10 In Example 8, an undercoat film of aluminum hydroxide (0.2% in terms of alumina with respect to the phosphor) was previously formed on the phosphor surface using an aqueous sodium aluminate solution. Is C in the same manner as in Example 8.
An o-Zn-Si-based pigmented blue light-emitting phosphor was obtained.

Comparative Example 1 100 parts by weight of ZnS: Ag, Cl blue light emitting phosphor, CoO.Z having an average particle size of 0.5 μm
5.5 parts by weight of nO · SiO ₂ blue pigment and SBR emulsion as a binder (JSR manufactured by Nippon Synthetic Rubber Co., Ltd.)
(-0591) 0.3 part by weight (resin amount per 100 parts by weight of phosphor) was added to 150 parts by weight of demineralized water to form a slurry, the pH was adjusted, and the pigment was attached to the phosphor. Next, the mixture was filtered and dried at 120 ° C. for 15 hours to obtain a blue light-emitting phosphor with a pigment.

Comparative Example 2 In Comparative Example 1, ZnS:
Ag, instead of Cl blue phosphor, (Ba _{0. 5} Mg
_0.5 ) O.3.5 Al ₂ O ₃ : A blue light-emitting phosphor with a Co-Zn-Si pigment was obtained in the same manner as in Comparative Example 1 except that a blue light-emitting phosphor was used.

(Evaluation Method of Phosphor) Attached amount of pigment: A phosphor with a pigment is dissolved with a flux, and the metal in the solution is inductively coupled with a high frequency plasma emission spectrometer (I).
CP) and converted to the amount of oxide relative to the phosphor. Agglomeration degree: The particle size was measured and evaluated with a Coulter counter measuring device. The smaller the particle size and the closer to the raw material phosphor, the less aggregation. Pigment adhesion: After shaking the phosphor with pigment in water containing 0.1% of a surfactant, leave it for 2 hours and examine the transparency of the supernatant. It was evaluated on a scale.

(Phosphor Evaluation Results) Table 1 shows the evaluation results of the phosphors with pigments produced in Examples and Comparative Examples. The pigmented phosphors of the examples were found to be superior to those of the comparative example, when judging the degree of aggregation and the pigment adhesion force comprehensively.

[0033]

[Table 1]

[0034]

According to the present invention, by employing the above-described structure, it becomes possible to produce a pigmented blue light-emitting phosphor having a small amount of agglomeration at the time of pigment attachment and a good pigment adhesion.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-7169 (JP, A) JP-A-52-91787 (JP, A) JP-A-55-45712 (JP, A) JP-A 54-1979 72783 (JP, A) JP-A-56-875 (JP, A) JP-A-59-131652 (JP, A) JP-A-63-319216 (JP, A) JP-A-4-55324 (JP, A) JP-A-63-50321 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09K 11/08-11/89 H01J 29/20

Claims (5)

(57) [Claims] 1. A method for producing a blue light-emitting phosphor with a pigment, comprising: an aqueous solution or an aqueous dispersion containing cobalt and zinc;
An aqueous solution or dispersion containing silicon, a dispersion of a blue light-emitting phosphor, and a pH adjuster or a precipitant are mixed to form a coprecipitate of cobalt, zinc and silicon, and the coprecipitate and blue light are emitted. The mixture with the phosphor is filtered, washed with water, and then dried,
A method for producing a pigmented blue light-emitting phosphor characterized by firing. 2. A method for producing a pigmented blue light-emitting phosphor, comprising: an aqueous solution or an aqueous dispersion containing cobalt and zinc;
An aqueous solution or dispersion containing silicon, a dispersion of a blue light-emitting phosphor, and urea are mixed, and the mixed slurry is heated to produce a coprecipitate of cobalt, zinc and silicon, and the coprecipitate and After filtering the mixture with the blue light-emitting phosphor and washing with water,
A method for producing a pigmented blue light-emitting phosphor, which is dried and fired. 3. The method for producing a blue light-emitting phosphor with a pigment according to claim 1, wherein the mixture of the coprecipitate and the blue light-emitting phosphor is subjected to a hydrothermal synthesis treatment to adhere the pigment to the surface of the phosphor. A method for producing a pigmented blue light-emitting phosphor, wherein the phosphor is filtered, washed with water, and dried. 4. A method for producing a blue light-emitting phosphor with a pigment, comprising dissolving an alkoxide containing cobalt, zinc and silicon in an organic solvent, adding and mixing the blue light-emitting phosphor, and co-precipitating as a metal oxide by hydrolysis. And the mixture of the coprecipitate and the blue emitting phosphor is filtered, washed, and dried,
A method for producing a pigmented blue light-emitting phosphor characterized by firing. 5. A method for producing a pigmented blue light-emitting phosphor, comprising dissolving or slurrying an organometallic compound containing cobalt, zinc and silicon in an organic solvent, adding and mixing the blue light-emitting phosphor, and then subjecting the mixture to heat and pressure treatment. And applying the metal oxide to the surface of the phosphor as a metal oxide, filtering and washing the phosphor, and drying the phosphor, followed by drying.