JPH0641526A - Production of blue luminus fluorescent substance with pigment - Google Patents

Abstract

PURPOSE:To produce a blue luminous fluorescent substance with Co.Zn.-Si-based pigment capable of controlling aggregation of pigment at the time adhesion of pigment to a fluorescent substance and bonding a large amount of pigment to the fluorescent substance with high adhesion force without using a binder. CONSTITUTION:An aqueous solution or a water dispersion containing Co and Zn is blended with an aqueous solution or a water dispersion containing Si, a blue luminous fluorescent substance dispersion and a pH adjuster, or urea instead of the pH adjuster to form a coprecipitate, which is filtered, washed with water, dried and burnt or subjected to hydrothermal synthetic treatment, then filtered, washed with water and dried to produce the blue luminous fluorescent substance with pigment. Or an alkoxide containing Co, Zn and Si and the blue luminous fluorescent substance are mixed with an organic solvent and hydrolyzed to form a coprecipitate, which is filtered, washed with water and dried to produce the blue luminous fluorescent substance with pigment.

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 It is known that a filter material that absorbs reflection of external light on a fluorescent screen is attached to the surface of a phosphor in order to improve the contrast of an image of a color cathode ray tube or a fluorescent display tube. Further, a filter material may be attached to the surface of the phosphor in order to sharpen the emission spectrum of the phosphor. The blue light emitting phosphor with pigment is
Usually, a cobalt blue-based pigment (pigment containing cobalt aluminate as a main component) or a cobalt / zinc / silicon-based 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 surface of the phosphor, but the method in which the pigment is adhered using a binder has a problem that the pigments agglomerate at the time of adhesion to deteriorate the characteristics of the phosphor film. In addition, in recent years, there is a demand for improvement in contrast, and it is necessary to increase the amount of pigment attached by about 5 times that of the conventional method. However, since an increase in the amount attached increases the amount of binder, it is necessary to obtain excellent fluorescent film characteristics. However, the increase in the amount of pigment adhered causes a problem that the pigment once adhered is peeled off at the time of application to the cathode ray tube.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, suppresses the aggregation of the pigment when the pigment is attached to the phosphor, and is capable of adhering a large amount of pigment with a strong adhesive force. It is intended to provide a method for manufacturing a light emitting phosphor.

[0004]

The present invention is a method for producing a pigmented blue light emitting phosphor as follows. In the method for producing a blue light emitting phosphor with a pigment, an aqueous solution or an aqueous dispersion containing cobalt and zinc, an aqueous solution or an aqueous dispersion containing silicon, a dispersion of a blue emitting phosphor, and a pH adjusting agent or a precipitating agent. Pigmented blue light emission characterized by mixing to form a coprecipitate of cobalt, zinc and silicon, filtering the mixture of the coprecipitate and the blue-emitting phosphor, washing with water, drying and firing. Method for manufacturing phosphor.

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

In the method for producing a blue light-emitting phosphor with a pigment as described above or described, the mixture of the coprecipitate and the blue light-emitting phosphor is subjected to hydrothermal synthesis treatment, filtered, washed with water, and dried. And a method for producing a blue light-emitting phosphor with a pigment.

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

[0008] An organometallic compound containing cobalt, zinc and silicon is dissolved or slurried in an organic solvent, a blue light emitting phosphor is added and mixed, and then heat and pressure treatment is applied to deposit a metal oxide on the phosphor surface. A method for producing a pigmented blue light-emitting phosphor, which comprises filtering, washing, and drying the phosphor.

[0009]

As a result of various investigations on the blue light-emitting phosphor with pigment, the present inventors adhered the Co / Zn / Si-based blue pigment to the phosphor without using a binder to prevent the pigment from aggregating at the time of pigment adhesion. The inventors have found that it can be suppressed and improve the adhesion of the pigment to the phosphor, and completed the present invention.
The oxide-based molar ratio of the xCoO.yZnO.zSiO ₂ system blue pigment used here is 0.05 ≦ x / z ≦ 1.
5, 0.1 ≦ y / z ≦ 2.0, especially 0.2 ≦ x / z ≦
1.0 and 0.3 ≦ y / z ≦ 1.7 are preferable. Outside of this range, the color tone changes, so it is not suitable for combination with a blue-emitting phosphor.

The first method for producing a pigmented blue light-emitting phosphor of the present invention is an aqueous solution or aqueous dispersion containing cobalt and zinc (referred to as liquid I), an aqueous solution containing silicon or an aqueous dispersion (referred to as liquid II). ), A dispersion of a blue-emitting phosphor, and
A pH adjusting agent or a precipitating agent 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 then baked. A method for producing a characteristic blue light-emitting phosphor with a pigment. The formation of the above coprecipitate is carried out by preparing a liquid I, a liquid II, and a dispersion liquid of the blue light emitting phosphor in advance, then mixing them at the same time, adding a pH adjusting agent or a precipitating agent, or After the light emitting phosphor is dispersed in the liquid I or the liquid II, another liquid and a pH adjusting agent or a precipitating agent can be mixed to obtain a coprecipitate.

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

In the second method for producing the pigmented blue light emitting phosphor of the present invention, urea is added in place of the pH adjusting agent or the precipitating agent in the first producing method, and the mixed slurry is heated to obtain cobalt, zinc and The other condition is a method for producing a pigmented blue light-emitting phosphor in the same manner as the first production method except that a silicon coprecipitate is formed. 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 drying and firing furnace can be used.

The third method for producing the blue light-emitting phosphor with pigment of the present invention is the same as the first or second production method, but instead of firing.
The above coprecipitate-containing mixed slurry was placed in a pressure vessel to obtain about 1
It 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.

A fourth method for producing a pigmented blue light emitting phosphor of the present invention is to dissolve an alkoxide containing cobalt, zinc and silicon in an organic solvent, and then add and mix the blue light emitting phosphor to hydrolyze the metal. A method for producing a pigmented blue light-emitting phosphor characterized by comprising coprecipitating as an oxide, filtering a mixture of the coprecipitate and the blue light-emitting phosphor, washing, drying and firing. As the solvent, ethanol, methanol and the like can be used, and as the alkoxide of cobalt, zinc and silicon, dimethoxycobalt, diethoxycobalt, dimethoxyzinc, diethoxyzinc,
Tetramethoxy silicon, tetraethoxy silicon, etc. can be used. At the time of hydrolysis, it is preferable to heat at 30 to 40 ° C. while adding an appropriate amount of ammonia water.
The firing conditions are the same as in the first manufacturing method, and the same drying and firing furnace can be used.

In a fifth method for producing a blue light emitting phosphor with pigment of the present invention, an organometallic compound containing cobalt, zinc and silicon is dissolved in an organic solvent and the blue light emitting phosphor is added to prepare a mixed slurry. After that, put it in a pressure vessel for about 100-5
This is a method for producing a blue light emitting phosphor with a pigment by heat and pressure treatment in a temperature range of 00 ° C., preferably 200 to 400 ° C., and 1,4 butanediol, toluene, xylene or the like is used as an organic solvent. As the organometallic compound of cobalt, zinc and silicon, dimethoxycobalt, diethoxycobalt, tetramethoxysilicon, tetraethoxysilicon, zinc acetate or the like can be used.

In the above production method, it is also possible to improve the filter characteristics by incorporating an oxidizing agent into the aqueous solution or the aqueous dispersion to promote the oxidation reaction. Hydrogen peroxide, sodium peroxodisulfate, or the like can be used as the oxidizing agent. Further, in the above manufacturing method, the filter characteristics may be improved by irradiating the dried pigmented blue light emitting phosphor with vacuum ultraviolet rays or short wavelength ultraviolet rays in a vacuum or an inert atmosphere, instead of the baking treatment. It is possible. The intensity of vacuum ultraviolet rays or short wavelength ultraviolet rays 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, for the purpose of improving the adhesion of the pigment to the blue light emitting phosphor and inactivating the phosphor base, an undercoat is attached in advance to the surface of the blue light emitting phosphor in the above manufacturing method. be able to. As the undercoat, A
Metal oxides or hydroxides such as 1, Zn, Si, Ti, Co and Zr can be used. In the coprecipitation step and / or the calcination step of the above-mentioned production method, various mineralizers and other elements can be added, if necessary. Specifically, Li, Na, K, Ca, Mg, Ba, Fe, N
i, Cu, Mn, Ti, V, Al, Sn, Sb, Cr,
Pr, B, Mo, etc. may be contained. These elements can be added in the range of about 5% by weight or less in the attached pigment. If it exceeds this range, it becomes impossible to obtain a preferable color tone as a blue pigment.

Blue emitting firefly that can be used in the present invention
As an optical body, the emission spectrum is in the range of 380 to 500 nm.
It has the main part of the cuttle, specifically
Zinc bromide-based phosphor [ZnS: Ag, X (X is halogen or
Al), ZnS: Ag, M, X (M is Ga, In, etc., X
Is halogen or Al)], Y₂SiO_Five: Ce, Ca ₂
B_FiveO₉Cl: Eu, (Ba_xMg_1-x) O ・ nAl₂
O₃: Eu (0 ≦ x ≦ 1; 1.5 ≦ n ≦ 4.5), Sr
Si₃O₈Cl_Four: Eu, CaWO_Four, CaWO_Four: P
b, BaFCl: Eu, Gd₂O₂S: Tb, ZnS:
Zn etc. can be mentioned. In addition, the above blue pigment
The amount of adhesion is in the range of 0.1 to 15% by weight with respect to the phosphor.
preferable. If the adhered amount falls below the above lower limit, the filter
If the effect is too small, and if the upper limit is exceeded, the emission brightness will be insufficient.
It may not be a 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 this, 1N aqueous sodium hydroxide solution was added little by little to adjust the pH to 8.5 and coprecipitate. After that, the slurry was filtered, washed with water, and dried at 120 ° C. for 15 hours. Then, the dry mixture was baked at 1000 ° C. for 1 hour to obtain a Co.Zn.Si based pigmented blue light emitting phosphor.

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 (S manufactured by Nissan Chemical Co., Ltd.)
T-20L) solid content 1.53 parts by weight, 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 light-emitting phosphor is added with deionized water 150 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. Then, 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 pigment was obtained.

(Example 3) Diethoxycobalt 3.80
Parts by weight, diethoxyzinc 3.94 parts by weight, tetraethoxysilicon 5.30 parts by weight, 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 this, 2% of 28% ammonia solution was added.
0 part by weight was added and the mixture was 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.
A blue light emitting phosphor with an O.SiO ₂ pigment was obtained.

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

(Example 5) Diethoxycobalt 3.80
Parts by weight, 5.59 parts by weight of zinc acetate dihydrate, 5.30 parts by weight of tetraethoxy silicon, and 100 parts by weight of ZnS: Ag, Cl blue light emitting phosphor to 150 parts by weight of 1,4 butanediol at room temperature. It was dissolved and made into a slurry, which was purged with nitrogen in an autoclave and then reacted at 300 ° C. for 3 hours. After the reaction was filtered, washed with methanol, to obtain a CoO · ZnO · SiO ₂ type pigment-attached blue-emitting phosphor and air dried.

(Example 6) After the coprecipitation in Example 1, 5 parts by weight of sodium peroxodisulfate was added and boiled. After that, it is filtered, washed with water and dried, and then in vacuum (10 ^-5
mmOg) and irradiate ultraviolet rays (wavelength 147 nm) (ultraviolet intensity 8 mW / cm ² ) to CoO / ZnO / SiO _2.
A blue light emitting phosphor with a pigment was obtained.

Example 7 In Example 1, an undercoating film of aluminum hydroxide was previously formed on the surface of the phosphor by using an aqueous solution of sodium aluminate (0.2% of the phosphor in terms of alumina), After that, 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
Liquid I was prepared by dissolving 7 parts by weight and 3.46 parts by weight of zinc chloride in 50 parts by weight of demineralized water to form liquid I, and dissolving 1.53 parts by weight of silica solid glass of potassium water glass in 10 parts by weight of demineralized water. And On the other hand, (Ba _0.5 Mg _0.5 ) O · 3.5 Al
₂ O ₃ : Eu blue light emitting phosphor 100 parts by weight is added to demineralized water 10
Liquid III was obtained by dispersing in 0 part by weight. Keep Liquid III at 30 ° C and mix Liquid I and Liquid II at a constant speed with stirring.
It was added for 0 minutes and coprecipitated. During this time, the liquid III is 0.1
N sodium hydroxide solution or O.N. The pH was adjusted to 8.0 to 8.5 with 1N hydrochloric acid. After the addition was completed, the mixture was aged for 1 hour. Then, the dispersion is filtered and washed with water, and
It was dried at 0 ° C. for 15 hours. The dry mixture is then 10
It was baked at 00 ° C. for 1 hour to obtain a blue light emitting phosphor with a Co / Zn / Si-based pigment.

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

(Example 10) In Example 8, an undercoating film of aluminum hydroxide (0.2% in terms of alumina based on the phosphor) was previously formed on the surface of the phosphor by using an aqueous solution of sodium aluminate. In the same manner as in Example 8
A blue light emitting phosphor with an o.Zn.Si pigment 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 Japan Synthetic Rubber Co., Ltd.
-0591) 0.3 parts by weight (resin amount per 100 parts by weight of the phosphor) was added to 150 parts by weight of demineralized water to form a slurry, and the pH was adjusted to attach the pigment to the phosphor. Then, after filtering, it was dried at 120 ° C. for 15 hours to obtain a pigmented blue light emitting phosphor.

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

(Evaluation Method of Phosphor) Pigment Adhesion: Pigmented phosphor is melted with a fluxing agent, and the metal in the solution is inductively coupled high frequency plasma emission spectroscopic analyzer (I
CP), and converted into the amount of oxide with respect to the phosphor. Aggregation degree: The particle size was measured and evaluated by a Coulter counter measuring device. The smaller the particle size and the closer to the starting phosphor, the less aggregation. Pigment adhesion: The pigmented phosphor is shaken in water containing 0.1% of a surfactant and left for 2 hours to check the transparency of the supernatant. The grade was evaluated.

(Results of Phosphor Evaluation) Table 1 shows the results of evaluation of the pigmented phosphors produced in Examples and Comparative Examples. It can be seen that the pigmented phosphors of the examples are superior to those of the comparative example when comprehensively judging the degree of aggregation and the pigment adhesion.

[0033]

[Table 1]

[0034]

EFFECTS OF THE INVENTION By adopting the above-mentioned constitution, the present invention makes it possible to produce a blue light-emitting phosphor with a pigment, which has less aggregation at the time of pigment adhesion and has a good pigment adhesion.

Claims (5)

[Claims] 1. A method for producing a blue light-emitting phosphor with a pigment, which comprises an aqueous solution or an aqueous dispersion containing cobalt and zinc,
An aqueous solution or water dispersion containing silicon, a dispersion of a blue light emitting phosphor, and a pH adjusting agent or a precipitating agent 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, then dried,
A method for producing a pigmented blue light-emitting phosphor, which comprises firing. 2. A method for producing a pigmented blue light-emitting phosphor, which comprises an aqueous solution or an aqueous dispersion containing cobalt and zinc,
A silicon-containing aqueous solution or dispersion, a blue-emitting phosphor dispersion, and urea are mixed, and the mixed slurry is heated to form a coprecipitate of cobalt, zinc, and silicon. After filtering the mixture with the blue-emitting phosphor and washing with water,
A method for producing a blue light-emitting phosphor with a pigment, which comprises drying and firing. 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 hydrothermal synthesis treatment to attach the pigment to the surface of the phosphor. A method for producing a pigmented blue light-emitting phosphor, which comprises: filtering the phosphor, washing with water, and then drying. 4. A method for producing a blue light emitting phosphor with a pigment, wherein an alkoxide containing cobalt, zinc and silicon is dissolved in an organic solvent, the blue light emitting phosphor is added and mixed, and then hydrolyzed to coprecipitate as a metal oxide. 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, which comprises firing. 5. A method for producing a blue light emitting phosphor with a pigment, wherein an organometallic compound containing cobalt, zinc and silicon is dissolved or slurried in an organic solvent, and the blue light emitting phosphor is added and mixed, followed by heat and pressure treatment. A method for producing a pigmented blue light-emitting phosphor, which comprises applying a metal oxide as a metal oxide to the surface of the phosphor, filtering and washing the phosphor, and then drying.