JPS63289087A - Binder-containing phosphor and production thereof - Google Patents

Abstract

PURPOSE:To provide a phosphor with which a pulverization step can be omitted in the phosphor application process for manufacturing a lamp and the amt. of a binder can be greatly reduced and which comprises a phosphor substrate and a binder applied onto the particle surface thereof. CONSTITUTION:A phosphor having a binder applied to the particle surface thereof is used as a phosphor to be applied onto the inner surface of a discharge bulb. Application of the binder is accomplished by e.g., spraying a slurry of a particulate binder composed of calcium pyrophosphate, etc. during phosphor drying or by performing wet mixing of a particulate binder prior to phosphor drying. When the resulting phosphor is used in the manufacture of a lamp, since the binding agent has already been uniformly bound to the particle surface of the phosphor, it is possible to apply a phosphor suspension contg. suspended phosphor particles, irrespective of an aq. type or an org. solvent type, without the necessity of performing wet pulverization of a binder. As compared with the conventional phosphor, the amt. of the binder can remarkably be reduced, and improvement can be attained in the initial light output and output maintenance after the lapse of a prolonged period of time with respect to a lamp.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a phosphor for a lamp, and particularly to a novel phosphor in which a binder is attached to the surface of the phosphor. Techniques and Problems Thereof] In general, one method for coating a discharge lamp, such as a fluorescent lamp, with a phosphor is to use an organic solvent in which a binder in a phosphor dispersion is dissolved in an organic solvent such as butyl acetate or xylene. There is a solvent type and an aqueous type in which the binder is dissolved in water. In both of these methods, the phosphor and fine particles of calcium chloride (CazPzO7), calcium and barium chloride (CaO and BaO) are mixed in the dispersion liquid.・B? 03)
, it is necessary to mix a binder such as aluminum oxide (AI, O,).

However, conventionally, the binder to be mixed plays an important role in adhering the phosphor particles to the inner surface of the bulb.
Yes4I! For both solvent and water-based types, it is necessary to pulverize the binder together with the organic solvent in the case of the 411 solvent type using a mechanical pulverization process such as a ball mill. The process requires a place to install a ball mill, etc., and it is difficult to uniformly pulverize the binder using a mechanical pulverization process such as a ball mill. Uniform pulverization cannot be carried out, and a great deal of time and labor is required, so there has been a strong desire to eliminate mechanical pulverization using a ball mill or the like in the phosphor coating process.

Furthermore, since the binder itself does not emit light, it has been strongly desired to reduce the amount of binder used in view of the luminescent characteristics of fluorescent lamps.

By the way, in order to avoid finely pulverizing the binder in the phosphor application process during lamp manufacture, it is conceivable to slurry the binder in a fine powder state in a solution during the manufacture of the binder. Since the binder manufacturer and the lamp manufacturer are different, the mode of transportation must be considered, and if the binder is transported in a slurry state, there is a problem in that the cost is high. Furthermore, in the case of an organic solvent type, the risk of fire or the like must be taken into consideration in the storage location, which raises the problem of disaster prevention measures in addition to transportation costs.

[Problems to be solved by the invention] This invention was made in view of the above circumstances, and
The purpose of this is to enable the phosphor particles to be applied to the inner surface of the bulb without mechanical pulverization during the phosphor coating process during fluorescent lamp manufacturing, and to also allow the phosphor particles to adhere to the coated surface. An object of the present invention is to provide a binder-attached phosphor that can reduce the amount of binder used.

[Means for Solving the Problems] The present inventor reduces the pulverization process using a ball mill or the like in the phosphor coating process during lamp manufacturing by attaching a binder to the surface of the phosphor particles. Based on the idea that this is possible, we conducted various experiments. As a result, the above object was unexpectedly solved by providing a phosphor in which a particulate binder was attached to the surface of the phosphor particles, that is, a binder-coated phosphor. I discovered something new.

Moreover, this binder-attached phosphor can be produced by spraying a fine particle binder slurry during drying in the phosphor manufacturing process, or by wet mixing before the product drying process in the phosphor manufacturing process. , manufactured by a simple method.

[Function] In the phosphor coating process during lamp manufacturing using conventional lamp phosphors, for both water-based and organic solvent types, before the mixing process of phosphor particles and binder, , it was necessary to wet-pulverize the powdered binder using mechanical pulverization means such as a ball mill.

However, in the binder-attached phosphor of the present invention, the binder is already uniformly adhered to the surface of the phosphor, so wet pulverization of the binder is not necessary for both the aqueous type and the organic solvent type. A phosphor suspension in which phosphor particles are suspended can be applied without having to do so.

Furthermore, as shown in the schematic diagram of FIG. 1, in the binder-attached phosphor obtained by the method of the present invention, the binder particles 2 are uniformly attached to the surface of the phosphor particles l. . If you compare,
In the conventional method, that is, when binder particles are mixed with Hinter and phosphor particles in the phosphor coating step during lamp manufacturing, as shown in the schematic diagram of FIG. particle 2
is concentrated in the contact area between the phosphor particles 1 and the phosphor particles 1 or the contact area between the phosphor particles 1 and the bulb 3, and is deposited in a large amount. In other words, with the phosphor of the present invention, the binder can be easily attached to the phosphor particles, and moreover, the binder can be attached to the surface of the phosphor particles in the conventional phosphor coating process during lamp manufacturing. Compared to the case of mixing, the amount of binder used can be significantly reduced. That is, by reducing the binder that does not participate in the light emission of the phosphor, the luminous flux of the lamp after 100 hours increases by about 2% with approximately the same coating amount and approximately the same binding strength.

Advantageously, in the case of the organic solvent type, phosphor deterioration is less likely to be caused by the binding agent entrapping the binder, such as nitrocellulose, during baking in the phosphor coating process.

[Example] (Example 1) First, a case will be described below in which a water-based type phosphor with a binder of the present invention is applied to a lamp bulb.

As the phosphor, a calcium halophosphate phosphor (average particle size 6 μm) obtained by a conventional method was used.

On the other hand, as a stone agent, the center particle size is reduced to 0 using a wet ball mill.
．． 20 weights of pyrophosphoric acid calcyano prepared to 5 μm: U
t% water-soluble slurry was used.

After firing the phosphor, it is crushed and washed with water.
While moving I l 00 kg into the transport pipe with hot air, 2.5 [1] of a water-soluble slurry of calcium pyrophosphate, which is a binder, was sprayed into the transport pipe, and the binder-attached phosphor was removed using a back filter. Compiled.

In the binder-attached phosphor thus obtained, 0.5% by weight of the binder was attached to the phosphor.

By adjusting the jets M-Ml in a similar manner, 1.0% of the binder was applied to the phosphor, respectively. 2.3. 4. , 5% by weight was deposited.

Electron micrographs confirmed that in these binder-attached phosphors, calcium pyrophosphate particles were uniformly adhered to the surface of the calcium halophosphate phosphor particles.

Then, in order to optimize the coating amount of the coating film in a fluorescent lamp, these binder-attached phosphors were suspended in an aqueous solution containing 1% by weight of hydroxypropylcellulose, using an aqueous coating method. A 40W fluorescent lamp was manufactured by applying coating film 1 to the inner surface of a bulb with a diameter of 32 mm.

For comparison, /IOW fluorescein was prepared by a conventional method, i.e., by the aqueous type coating method described above, except that the binder particles were mixed with the binder and phosphor particles in the phosphor coating step during lamp manufacture. Made a lamp.

FIG. 3 shows the relative emission intensity of the fluorescent lamp as a function of the amount of binder added. The relative luminescence intensity is 1 with respect to the phosphor.
The light output intensity of the fluorescent lamp when % by weight of the binder is deposited is 100%.

Further, the amount of binder added in FIG. 3 is compared between the example of the present invention and the conventional example when the phosphor coating strength is almost the same.

As is clear from FIG. 3, the amount of binder added in this example can be reduced to about 70% compared to the conventional method, and moreover, the binder-attached phosphor of this example is used. Fluorescent lamps have a light output of 0. It improved by 5-5%. Although not shown, 1
00 hours B! The lamp light output after the lapse of time had almost the same tendency as the initial light output described above, that is, the light output maintenance rate (
Even relative light output (relative light output based on initial light output) is 0.5 to 5%.
Improved.

(Example 2) Next, a case will be described below in which an organic solvent type phosphor with a binder of the present invention is applied to a lamp bulb.

As the phosphor, 100 kg of the same calcium halophosphate phosphor (average particle size 6 μm) as in Example 1 was used. On the other hand, as a binder, add 1 kg of finely divided calcium pyrophosphate to 4 ml of pure water.
Suspension A prepared by suspending 1 kg of boric acid to have a center particle size of 0.5 μm and 1 kg of tobarium boric acid in 4 kg of pure water.
to a central particle size of 0. A binder particle suspension was used which was mixed and stirred with suspension B prepared to have a particle size of 5 μm.

This binder particle suspension was sprayed onto the calcium halophosphate phosphor in the same manner as in Example 1, and dried to adhere the binder particles to the surface of the phosphor particles. I got it.

Different from Example 1, the diameter 2 was applied using an organic solvent type coating method.
I made a 4012 light lamp with a 7mm bulb. That is, a phosphor with a binder was suspended in a butyl acetate solution in which 1% by weight nitrocellulose as a binder was dissolved, and this suspension was applied to a bulb.

For comparison, a 40W fluorescent lamp was manufactured using the same coating method as described above except that the binder particles were mixed with the binder and the phosphor particles.

As a result, compared to conventional lamps, when the phosphor coating process and binding strength of the lamp coating are almost the same, the fluorescent lamp using this example has an initial light output and a light output maintenance rate after 100 hours. It improved by about 2%.

In addition, in the conventional organic solvent type coating method, approximately 3 kg of binder is used for 100 kg of calcium halophosphate phosphor.
The amount of adhesion to the phosphor in this example was approximately 2 kg, which was a reduction of 1 kg.

(Implementation f943) Next, a case where the present invention is applied to a three-wavelength type mixed phosphor using an organic solvent type will be described below.

As the phosphor, trivalent Eurobiu-11-activated yttrium oxide (Y?03: EIJ3+) is used as the red component, and cerium and terbinium-11-activated lanthanum phosphate (LaPO4: Ce, Tb) phosphor is used as the green component. As a body,
And the blue component contains divalent europium-activated strontium calcium barium chlorophosphate ((S r, C
a, Ba) I O(PO4) 6C[! z:Eu2
+) Fluorescent material and three-wavelength fluorescent material each 40.40.2
Approximately 160 kg of each phosphor suspension is suspended in pure water.
．． Adjust to 160.20G.

On the other hand, as a binder, finely powdered aluminum oxide is suspended in pure water, and the concentration of this binder particle suspension is adjusted to 10 weight by weight and the center particle diameter to 0.5 μm.

While stirring each of the previously prepared phosphor suspensions, add a binder particle suspension to each phosphor at a binder weight of 1.
Add to 5% by weight.

After each suspension is dehydrated using a suction type filter, the three component phosphor particles to which binder particles are attached by a wet method are dried.

The above implementation f carried out by the method of adhering binder particles by spraying
Similar to il and 2, binder particles were uniformly adhered to the surface of the binder-attached phosphor particles obtained in this example, as determined by electron microscopy and mirror photography.

Each dried phosphor particle was suspended in a butyl acetate solution containing 1% nitrocellulose to prepare a phosphor suspension so that the color temperature of the lamp would be 5000K. This phosphor suspension was applied to a bulb with a diameter of 27 mm.
A W fluorescent lamp was prepared, and for comparison, a 40 W fluorescent lamp was also prepared using the same coating method as described above except that the binder particles were mixed with the binder and the phosphor particles.

As a result, compared to the conventional lamp, when the phosphor coating film Bm of the lamp coating film and the binding strength are almost the same, the lamp using the binder-attached phosphor of the present invention has a lower initial light output and 100 hour Both of the optical output maintenance rates after the elapse of time were improved by about 1.5%.

In addition, in the conventional organic solvent type coating method, approximately 2.25 kg of binder is required for 100 kg of three-wavelength mixed phosphor.
Compared to the required amount, the amount of adhesion to the phosphor in this example was approximately 1.5 kg, which was a reduction of 0.75 kg.

[Effects of the Invention] According to the present invention, in the phosphor coating process during lamp manufacturing using a binder-attached phosphor, wet pulverization treatment of the binder is required for both aqueous type and organic solvent type phosphors. A phosphor that suspends phosphor particles without the need for irradiation! ! j. A suspension can be applied.

Further, according to the method of the present invention, the binder can be easily attached to the phosphor particles, and moreover, the binder can be attached to the surface of the phosphor particles in the phosphor coating film H5 step during conventional lamp manufacturing. Compared to the case where the binder is mixed, waste of the binder can be significantly reduced, and the initial light output of the lamp and the light output maintenance rate after 100 hours can be improved by 0.5 to 2%.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing how the binder-attached phosphor particles of the present invention are attached to a bulb, and FIG.
FIG. 3 is a schematic diagram showing the relationship between phosphor particles and binder particles in a conventional example, and FIG. 3 is a graph diagram showing the relationship between the amount of binder added and the relative luminescence output intensity.

Claims (8)

[Claims] (1) A phosphor with a binder, which is a phosphor to be coated on the inner surface of a bulb of a discharge lamp, characterized in that a binder is attached to the particle surface of the phosphor. (2) The binder-attached fluorescence according to claim 1, wherein the binder is an alkaline earth metal phosphate, borate, aluminum oxide, or a mixture thereof. body. (3) The adhesion amount of the above binder is 0.5 to 0.5 to the phosphor.
The phosphor with a binder according to claim 2, wherein the binder content is 5% by weight. (4) The binder-attached phosphor according to claim 1, wherein the phosphor is a mixed phosphor that is a mixture of two or more types of phosphors. (5) A binder-attached phosphor comprising a binder deposition step of depositing a fine powder binder on the surface of particles of the phosphor to be coated on the inner surface of a bulb of a discharge lamp. Production method. (6) A method for producing a binder-attached phosphor, characterized in that in the binder adhesion step, a fine powder binder having a center particle diameter in the range of 0.1 to 3 μm is used. (7) The above-mentioned binder attachment step is a patent characterized in that the fine powder binder is attached to the surface of the phosphor particles by spraying a fine powder binder slurry when drying the phosphor. A method for producing a binder-attached phosphor according to claim 6. (8) The binder adhesion step is characterized in that the fine powder binder is attached to the surface of the phosphor particles by wet-mixing the fine powder binder before drying the phosphor. A method for producing a binder-attached phosphor according to claim 6.