JPH06136286A - Blue pigment and the same pigment-bearing blue luminescent fluorescencer - Google Patents

Abstract

PURPOSE:To provide a blue pigment of high heat resistance, and to provide a blue pigment-bearing blue luminescent fluorescencer excellent in color tone stability, giving favorable blue luminescence even after baking process for cathode ray tube production through bearing the blue pigment. CONSTITUTION:The blue pigment is characterized by making (A) at least one kind of metal oxide, metal hydroxide or hydrate thereof adhere to the surface of CoO.ZnO.SiO2-based blue pigment particles. The other objective fluorescencer is characterized by making the above pigment adhere to the surface of a blue luminescent fluorescencer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blue pigment and a blue light emitting phosphor with a pigment 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 on a color cathode ray tube, a fluorescent display tube or the like, a method using a pigmented phosphor in which filter particles for absorbing reflection of external light on a phosphor screen are attached to the surface of the phosphor, and A method of using colored glass for a face plate of a cathode ray tube is known. The method of using colored glass for the face plate of the cathode ray tube is by reducing the transmittance of the glass,
Although the contrast can be relatively easily selected in the practical region, the brightness is significantly reduced because the absorption rate of not only the external light but also the light emitted from the fluorescent film is high.

Further, the method of using a pigmented phosphor having filter particles attached thereto is an effective method for improving the contrast without reducing the brightness of the screen as much as possible. On the other hand, filter particles may also be used to sharpen the emission spectrum of the phosphor. In this case, the reflectance of the filter particles is required to be high in the main emission wavelength region of the phosphor and low in other wavelength regions.
Due to this characteristic of reflectance, it is possible to absorb a light component that does not match the main light emitting region of the phosphor and improve the contrast of bright outside light. In the blue light emitting phosphor, a pigment that absorbs as little as possible near the emission peak of 450 nm and that absorbs as much as possible in other wavelength regions may be used.

As a blue pigment of this type, JP-A-54-2
Ultramarine (3NaAl ・ SiO ₂・ Na ₂
S ₂ ), dark blue (Fe ₄ [Fe (CN) ₆ ] ₃・ nH
₂ O), cobalt aluminate (CoO ・ nAl ₂ O ₃ ).
, Cerulean blue (CoO.nSnO ₂ ), copper sulfide (CuS), etc. have been proposed. However, the body color of cobalt aluminate, which is generally used as a blue pigment, does not match the emission spectrum of the blue phosphor.
Since the reflectance in the vicinity of nm is high, it is not effective for the purpose of improving the contrast.

Although some of the ultramarine blues that are practically used have excellent characteristics as compared with cobalt aluminate, they have extremely poor chemical stability, and therefore, have a process of adhering to a phosphor or a process of applying to a cathode ray tube. Has the drawback of fading. In order to prevent this discoloration, a method of coating a ultramarine blue pigment with a silicic acid compound is also known, but when it is applied to a cathode ray tube, its body color is significantly changed by electron beam irradiation, and the peak of the emission spectrum of the fluorescent screen is increased. Has the drawback of shifting.

On the other hand, the Japanese Patent Application No. 4 proposed by the inventors of the present invention.
The CoO.ZnO.SiO ₂ based blue pigment of the No. 114821 application is a well-balanced blue pigment having a color tone in the pigmented phosphor close to that of ultramarine blue and having higher fastness than ultramarine blue. However, in a recent CRT with a strong tendency toward high image quality, even if a CoO / ZnO / SiO ₂ based blue pigment is directly attached to the phosphor, the color stability is not always sufficient, and the color tone of the pigmented blue light-emitting phosphor is not sufficient. It is also required to further improve the heat resistance and the quality of the cathode ray tube.

[0007]

Therefore, the present invention solves the above-mentioned drawbacks and provides a blue pigment having excellent heat resistance, and
By adhering the blue pigment, it is intended to provide a pigmented blue light-emitting phosphor capable of obtaining blue light emission with an excellent color tone even after a baking step for manufacturing a cathode ray tube.

[0008]

The present invention is directed to CoO.Zn.
A blue pigment characterized in that at least one or more kinds of oxides, hydroxides and hydrates of these metals are attached to the surface of O.SiO ₂ type blue pigment particles, and the above-mentioned. A pigmented blue light-emitting phosphor characterized in that a blue pigment is adhered to the surface of a blue light-emitting phosphor.

The CoO.ZnO.SiO ₂ pigment is the same as the pigment described in Japanese Patent Application No. 4-114821. The metal constituting the oxide, hydroxide or hydrate attached to the surface of the CoO / ZnO / SiO ₂ pigment particles is Al, Zn, Si, Ti, Zr, Mg, In, S.
It can be selected from among b, Sn, Mo, Ta, Ce, Ge, Ga, Nb, etc., and particularly preferred is Al, Zn.
And Si.

The ratio of the metal compound attached to the surface of the pigment to the pigment is in the range of 0.5 to 200% by weight, particularly 2 to
A range of 50% by weight is preferred. When it is less than this range, the heat resistance is not sufficiently improved, and when it exceeds this range, the color tone becomes light due to the presence of the metal compound, which is not preferable. As a method of attaching the metal compound to the surface of the pigment particles, a neutralization precipitation reaction method of a soluble metal salt slurry in the presence of a pigment, an alkoxide method, or the like can be used.

The blue light-emitting phosphor that can be used in the present invention has a major part of the emission spectrum within the range of 380 to 500 nm, and specifically, it is a silver-activated zinc sulfide-based phosphor [ZnS: Ag, X (X is halogen or A
l), ZnS: Ag, M, X (M is Ga, In, etc., X is halogen or Al)], Y ₂ SiO ₅ : Ce, Ca ₂ B
₅ O ₉ Cl: Eu, (Ba _x Mg _1-x ) O.nAl ₂ O
₃ , Eu (0 ≦ x ≦ 1, 7 ≦ n ≦ 8), SrSi ₃ O _{8
Cl 4: Eu, CaWO 4,} CaWO 4: Pb, BaF
Examples include Cl: Eu, Gd ₂ O ₂ S: Tb, ZnS: Zn, and the like.

As a method of attaching the above-mentioned metal compound-attached blue pigment to the blue light emitting phosphor, for example, a method of adding an organic binder to a slurry in which the pigment and the phosphor coexist can be used. The amount of the above blue pigment attached to the blue light emitting phosphor is preferably in the range of 0.3 to 15% by weight. If the adhesion amount is less than the lower limit value, the filter effect is too small, and if it exceeds the upper limit value, the emission brightness becomes insufficient.

[0013]

The present inventors can improve the heat resistance of the pigment by adhering the metal compound to the surface of the pigment particle in the course of various studies on the blue light-emitting phosphor with CoO.ZnO.SiO ₂ pigment. In addition, it was possible to improve the color tone stability of the phosphor to which the pigment adheres. Although the reason for the improvement in heat resistance of the pigment is not clear, it is considered that the crushed surface appearing in the dispersion step after the pigment is baked is less susceptible to thermal deterioration by attaching the metal compound to the particle surface. A metal silicate or phosphate may be considered as a substance that adheres to the surface of the particles, but oxides, hydroxides, and hydrates thereof are used as in the present invention because of the ease of controlling the manufacturing process. Is more advantageous.

The metal compound-attached CoO.ZnO.
The SiO ₂ pigment can be used as a mixture with cobalt aluminate or ultramarine depending on the application, and the mixed pigment can be attached to the blue light emitting phosphor or the CoO.ZnO of the present invention.
It is also possible to mix and use a blue light emitting phosphor with a SiO ₂ pigment and a blue light emitting phosphor to which cobalt aluminate or ultramarine is attached. Further, as a method of applying the above-mentioned blue pigment or pigmented blue light-emitting phosphor to the face plate, the pigmented blue light-emitting phosphor is applied to the face plate or between the face plate and the blue light-emitting phosphor film. The method of applying as the above blue pigment layer can be used. As described above, the blue light-emitting fluorescent film containing the blue pigment particles makes it possible to obtain a high-contrast fluorescent screen that maintains brightness, and it is possible to provide a color cathode-ray tube that is easy to see even under bright outside light. . Furthermore, since the blue pigment of the present invention has excellent heat resistance as compared with conventional pigments, it is possible to stabilize the color tone of the resin molded and used at a relatively high temperature, and the stability of the color tone over time. Good and expected to be widely used.

[0015]

【Example】

(Production Example of Blue Pigment) 60 parts by weight of cobalt oxide (hereinafter,
103 parts of zinc oxide and 64 parts of silicon oxide are mixed and calcined in air at 1300 ° C. for 2 hours,
After cooling, dispersed by a ball mill and x having an average particle size of 0.6 μm
CoO.yZnO.zSiO ₂ pigment (x = 0.8, y =
1.3, z = 1.0) was obtained.

(Example 1) 10 parts of the above blue pigment, SiO
2.5 wt% in ₂ equivalent (to pigment) potassium water glass, 80 parts of demineralized water were slurried with 25 ° C., pH by addition of acetic acid =
The temperature was adjusted to 7, the temperature was raised to 70 ° C., and the mixture was stirred for 2 hours. Then, after decantation, filtration and washing, it was dried at 120 ° C. for 5 hours and passed through a 500 mesh sieve to obtain a SiO ₂ adhered blue pigment.

(Example 2) 10 parts of the above blue pigment and 80 parts of demineralized water were slurried and kept at pH = 7 with caustic soda while ₃ wt% of Al ₂ O ₃ equivalent (to pigment) aluminum nitrate 9 hydrate 20. % Aqueous solution was added at 25 ° C. with stirring. After the addition was completed, stirring was continued for 2 hours and the same post-treatment as in Example 1 was carried out to obtain an Al ₂ O ₃ -attached blue pigment.

(Example 3) 10 parts of the above blue pigment and 80 parts of demineralized water were slurried, and a 20% magnesium sulfate 20% aqueous solution in terms of MgO (against pigment) was stirred at 25 ° C while maintaining pH = 11 with caustic soda. While adding. After the addition was completed, stirring was continued for 2 hours and the same post-treatment as in Example 1 was carried out to obtain a MgO-adhered blue pigment.

Example 4 10 parts of the above blue pigment and 80 parts of demineralized water were slurried, and while maintaining pH = 8 with caustic soda, 30 wt% of ZnO equivalent (to pigment) zinc sulfate 2
A 0% aqueous solution was added with stirring at 25 ° C. After the addition was completed, stirring was continued for 2 hours and the same post-treatment as in Example 1 was carried out to obtain a ZnO-adhered blue pigment.

(Example 5) 10 parts of the above blue pigment, 2.9 parts of tetraethoxy titanium and 50 parts of ethanol were dissolved and slurried. While stirring this slurry, 5 parts of 28% aqueous ammonia solution was added, and the mixture was heated to 40 ° C. and reacted for 2 hours. Then, filter and wash with ethanol, then air-dry to remove ethanol and dry at 120 ° C for 5 hours.
After passing through a 500-mesh sieve, a TiO ₂ -attached blue pigment was obtained.

(Example 6) 10 parts of the above blue pigment, 2.2 parts of tetraethoxyzirconium, and 50 parts of ethanol were dissolved and slurried. While stirring this slurry,
5% aqueous ammonia solution was added, and the mixture was heated to 40 ° C. and reacted for 2 hours. Then, filter and wash with ethanol,
Then, it was air-dried to remove ethanol, dried at 120 ° C. for 5 hours, and passed through a 500-mesh sieve to obtain a ZrO ₂ -attached blue pigment.

(Examples 7 to 12) To 100 parts of silver activated zinc sulfide blue light emitting phosphor, 100 parts of distilled water was added to make a slurry, and 5 parts of each of the blue pigments obtained in Examples 1 to 6 was added thereto. , SBR emulsion 0.3 parts (resin amount per 100 parts of phosphor) were added and mixed, and the mixed slurry was adjusted to pH.
Adjust and attach the pigment to the phosphor, filter and then 120 ℃
After drying for 15 hours, a pigmented blue light emitting phosphor was obtained.

Comparative Example 1 The blue pigment used in Examples 1 to 6 (without a metal compound attached) was used as Comparative Example 1. (Comparative Example 2) Pigmented blue light-emitting phosphors were obtained by using the blue pigment of Comparative Example 1 instead of the pigment attached to the blue light-emitting phosphors in Examples 7 to 12.

(Heat Resistance Test) Examples 1 to 6 and Comparative Example 1
The blue pigment and the blue light-emitting phosphors with pigments of Examples 7 to 12 and Comparative Example 2 were subjected to a baking treatment at 500 ° C. for 1 hour, and the powder reflectance (%) at 450 nm before and after the treatment was measured. , Its rate of change [(front-back) / front ×
100%] and the results are shown in Table 1. As is clear from Table 1, the blue pigments of Examples 1 to 6 and Example 7
The pigment-emitting blue light-emitting phosphors of Nos. 12 to 12 showed less change in powder reflectance before and after baking as compared with Comparative Examples 1 and 2, and had good heat resistance.

[0025]

[Table 1]

(Color Stability Test) Example 7 and Comparative Example 2
The luminescent color of the blue light-emitting phosphor with pigment obtained in 1. was measured and shown in Table 2 by x and y values of CIE chromaticity coordinates. As is clear from Table 2, the pigment-containing blue light-emitting phosphor of Example 7 is superior in color tone stability to Comparative Example 2.

[0027]

[Table 2]

[0028]

According to the present invention, by adopting the above-mentioned constitution, it is possible to improve the heat resistance of the blue pigment and the blue light-emitting phosphor with pigment, and to maintain the color tone stability in the cathode ray tube manufacturing process. It became possible.

Claims (2)

[Claims] 1. A blue color characterized in that at least one or more kinds of oxides, hydroxides and hydrates of these metals are attached to the surface of CoO.ZnO.SiO ₂ type blue pigment particles. Pigments. 2. A blue light emitting phosphor with a pigment, characterized in that the blue pigment according to claim 1 is adhered to the surface of a blue light emitting phosphor.