KR100473817B1 - A process for producing glass frit powder for pdp pastes - Google Patents

Abstract

The present invention relates to a method for producing a glass frit powder for PDP paste, more specifically PbO, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , ZnO, BaO, TiO ₂ , ZrO ₂ , Bi ₂ O ₃ , Injecting a glass raw material consisting of CaO, MgO, CeO ₂ , Sb ₂ O ₃ into the platinum melting furnace to heat in a temperature range of 1,000 to 1,300 ℃ to produce a cullet; Primary dry grinding of the average particle diameter of the cullet using a ball mill or a disk mill in the range of 10 to 15 μm; Secondary dry grinding of the glass particles obtained above into a particle size of 1.5 to 2.5 μm with a dry grinding machine; Tertiary wet grinding of the glass particles obtained in the second grinding step to a particle size of 0.5 to 1.5 mu m; And it is a method for producing a glass frit powder for PDP paste, characterized in that it comprises a step of drying.

According to the method of manufacturing the glass frit powder for PDP paste of the present invention, it is possible to effectively control the particle size of 0.5 μm or less and the maximum particle size of 10 μm or more, so that the dispersion and the flow rate are uniform during manufacturing as the PDP paste, so that after formation of the partition or dielectric The sintered state is uniform and can improve the reflectance and transmittance.

Description

Manufacturing method of glass frit powder for PD paste {A PROCESS FOR PRODUCING GLASS FRIT POWDER FOR PDP PASTES}

The present invention relates to a method for producing a glass frit powder for PDP paste, and more particularly, to effectively control the fine particles and the maximum particle size. The present invention relates to a method for producing a glass frit powder for a PDP paste, in which the sintered state is uniform after formation and the reflectance and the transmittance can be enhanced.

The glass frit powder used in the production of PDP paste has a wide particle size distribution range and contains a large amount of fine particles, resulting in uneven dispersion and fluidity, and uneven sintering state or rough surface roughness during sintering after forming partitions or dielectrics. The reflectance or transmittance will drop.

That is, when the particle size of the glass frit powder is 0.5 μm or less, it is difficult to uniformly mix or disperse the filler and the glass frit powder when the oxide filler is added during paste production, and evenly mix the glass frit powder when the oxide filler is not added. However, due to the difficulty in dispersion, the sintered state is uneven and the range of the sintering conditions is considerably narrowed, making it unsuitable for mass production conditions. In addition, when the particle size of the glass frit powder is 10 µm or more, since the surface roughness is rough after the paste is manufactured and fired, there is a problem in that the reflectance or transmittance is decreased or the sintering temperature condition must be increased.

On the other hand, in recent years, the glass powder is spherical in shape to increase the filling density and the particle size in the range of 1.5 μm or less in order to improve the reflectance and transmittance, withstand voltage characteristics, and improve the luminance characteristics among the characteristics that affect the PDP quality. Efforts have been made to minimize the number of bubbles and the size of bubbles after manufacturing and firing the glass. However, in order to manufacture the particle size in the range of 1.5 μm or less, it is inevitable to wet grind. When wet grind for a long time, during sintering due to the change of physical properties of the glass powder due to the elution of Pb or B component in the glass composition for PDP Since the luminance characteristics are deteriorated due to the decrease in the breakdown voltage characteristics due to the abnormally generated giant bubbles and the decrease in transmittance due to cell defects caused by bubbles bursting, there is a disadvantage in that grinding should be performed in the shortest time possible. This situation needs to be complemented.

Therefore, in order to overcome the problems of the prior art as described above, in the production of glass frit powder for PDP paste, bubbles during firing that control the particle size of 0.5 μm or less and the maximum particle size of 10 μm or more and influence the quality of the final powder There is an urgent need for interprocess functional processing techniques for control.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to overcome the problem of the prior art as mentioned above, the present inventors developed the method which can control the particle size of the glass raw material powder for PDP paste to a certain range, and came to this invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a glass frit powder for PDP paste, which can control particles having a particle size of 0.5 μm or less and a maximum particle size of 10 μm or more and control an average particle size of 1.5 μm or less in manufacturing the glass frit powder for PDP paste. It is.

In addition, an object of the present invention is to provide a method for producing a glass frit powder for PDP paste to minimize the physical properties of the glass powder due to the elution of Pb or B component in the glass composition for PDP paste.

Hereinafter, the present invention will be described in detail.

The present invention is to prepare a glass frit powder for PDP paste, PbO, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , ZnO, BaO, TiO ₂ , ZrO ₂ , Bi ₂ O ₃ , CaO, MgO, CeO ₂ Or, by adding a glass raw material consisting of Sb ₂ O ₃ to the platinum melting furnace and heating in a temperature range of 1,000 to 1,300 ℃ to produce a cullet; Primary dry grinding of the average particle diameter of the cullet using a ball mill or a disk mill in the range of 10 to 15 μm; Secondary dry grinding of the glass particles obtained above into a particle size of 1.5 to 2.5 μm with a dry grinding machine; Tertiary wet grinding of the glass particles obtained in the second grinding step to a particle size of 0.5 to 1.5 mu m; And it is a method for producing a glass frit powder for PDP paste, characterized in that it comprises a step of drying.

Hereinafter, the present invention will be described in more detail.

In the present invention, the glass transition point, which is based on the three-component system of PbO, SiO ₂ , B ₂ O ₃ , is 350-550 ° C. and the softening point is 400-600 ° C., which is a low-temperature sinterable glass. It is possible to use a glass having. In particular, since the glass contains a large amount of PbO in its composition, Al ₂ O ₃ , ZnO, BaO, TiO ₂ , ZrO ₂ , Bi in order to reduce the corrosion of platinum by lead volatilization or lead, and to improve the water resistance and acid resistance ₂ O _3, an appropriate amount can be added to CaO, MgO, CeO _2, or Sb ₂ O _3, such as 1 or 2 or more of the ingredients of the components.

In the method for producing a glass frit powder for PDP paste according to the present invention, first, in the raw material mixing step, the corrosion of glass raw material and volatilization or platinum and the water resistance and acid resistance, which are mainly composed of PbO, SiO ₂ and B ₂ O ₃ , The additive amount for the basis weight is equally mixed by using a V-mixer, a tumbling mixer, or a gravity-free mixer.

Next, in the melting process of glass, the well-mixed raw material is put into a platinum crucible and melted for 30 to 60 minutes in the temperature range of 1000-1,300 degreeC. A stirrer was installed in the platinum crucible in order to prevent compositional variation due to an immiscible region which may occur due to a large amount of lead in the melt. The melt melted in the melting process produces a cullet (CULLET) to a thickness of 1mm or less by a roll mill.

The cullet obtained above is pulverized primarily by a ball mill or a disk mill. In the first coarse grinding process, the cullet is pulverized to an average particle diameter (D50) of about 10 to 30 µm, preferably 10 to 15 µm, and powdered into a 60 mesh sieve.

According to the present invention, the primary coarsely pulverized glass particles are finely pulverized through a dry grinding and a wet grinding process. Dry milling methods include, for example, ball mills, vibratory mills, jet mills, and the like. In the present invention, secondary dry milling is performed using a jet mill in order to reduce impurities and minimize a range of particle size distribution. Compared with other grinding methods, the jet mill can adjust the particle size distribution to a narrow range of 0.5 to 10 μm in size, thereby controlling the maximum particle size of 10 μm or more to improve the production yield and suppress the generation of fine particles of 0.5 μm or less. The average particle size of the glass particles obtained in the second dry grinding step is distributed in the range of 1.5 to 2.5 μm. In this step, the final marginal particle size difference occurs according to the glass composition, and it is important to grind to the particle size that can be pulverized as much as the second dry grinding.

The glass particles obtained in the second dry grinding step are pulverized by the third wet grinding. Wet grinding methods include, for example, ball mills, wear mills, and bead mills. In the wet grinding process, lead and boron components are eluted, causing variations in glass composition and water quality problems (Pb-containing environmental standards: 0.1 mg / l). It is advantageous to grind in the shortest possible time, as it may cause the grinding process, and it is necessary to grind with a narrow range of particle size distribution in order to keep the sintering conditions constant. The wet grinding methods can reduce grinding time in order of ball mill, wear mill, bead mill and minimize the range of particle size distribution. In the present invention, it is preferable that the second dry-pulverized glass particles by a bead mill are wet-pulverized to a particle size of 0.5 to 1.5㎛.

When the third wet grinding is performed in a nitric acid solution atmosphere of 2% or less, the grinding energy can be reduced, and the sphericalization of the particles can be reduced, thereby increasing the packing density, thereby further enhancing the effect of the functional treated portion. Here, when the temperature is 50 ° C. or more during grinding, the pickling effect of the glass is so great that it may cause an adverse effect of abnormal bubble generation during glass sintering due to damage of the glass particles themselves.

According to the present invention, in the drying step of the third wet pulverized glass particles, a method of vacuum drying, which can be dried at low temperature, is performed in order to minimize elution of Pb or B components by high temperature drying.

In addition, in the present invention, the calcination process is effected by performing a calcination process in an air atmosphere for at least 2 hours in a glass transition point region temperature of the glass frit powder for PDP paste, that is, in a temperature range of 350 to 550 ° C., to influence bubble control during sintering. Stabilize the powder particles, and the effect of improving the wettability, removal of residual organic foreign matter, water removal, etc. can be improved to improve the permeability through abnormal bubble control and to improve the cell defects due to bubble burst.

The calcination process is carried out in an atmosphere of at least 2 hours at a glass transition point temperature in a continuous heating furnace or batch heating furnace by laminating the dried glass powder in an alumina container to 1 cm or less.

Hereinafter, the present invention will be described in detail with reference to Examples.

Production Example

65% PbO, 15% SiO ₂ , 5% B ₂ O _3, 5% Al ₂ O ₃ , 2% ZnO, 2% BaO, 1% ZrO ₂ and a small amount of TiO ₂ , Bi ₂ A glass frit raw material composition for PDP paste consisting of O ₃ , CaO, MgO, CeO ₂ , and Sb ₂ O ₃ was added to a platinum melting furnace and heated at 1300 ° C. for 1 hour to prepare a cullet, which was used in the following examples.

Example 1

The cullet of the above production example was pulverized for 2 hours using a 1.5 L ball mill using a 10 ° alumina ball to prepare glass particles having an average particle diameter of 10 to 15 μm, and then the glass particles were injected into a dry jet mill and jetted. Table 1 shows the recovery rate for the average particle size of the raw material after grinding for 30 minutes at a nozzle pressure of 7 kg / cm 2 and an air flow rate of 8 m 3 / min.

As shown in Table 1, the recovery rate was very low when the raw material particle size after the first coarse pulverization is 30㎛ or more, and there was no significant change in the recovery rate below 15㎛. Therefore, it can be seen that it is efficient to control the particle size in the range of 10 to 15 µm in the first coarse grinding.

Recovery Rate of Dry Jet Mill According to Raw Material Size Grinding method Raw Material Average Grain Size (㎛) Average particle size after 1 hour of jet mill (㎛) % Recovery Dry jet mill 30 2.3 65 15 2.2 94 10 2.1 95 5 2.1 95

Example 2

The secondary dry pulverized glass particles obtained in Example 1 were subjected to third wet pulverization at a speed of 13 m / sec using 1 ° zirconia beads in a 1.2 L bead mill.

The slurry prepared by the third wet grinding was dried in accordance with the method of the following Table 2, respectively. In the drying method, oven drying was carried out at 150 ° C. for 24 hours, spray drying was carried out at 260 ° C. in an atomize manner, and vacuum vacuum drying was performed at 50 ° C. for 2 hours at a pressure of 10 ¹ to 10 ² torr.

Each powder dried according to the drying method was prepared as a paste by thermal stirring for 10 hours or more by mixing the glass powder and the vehicle. The vehicle was prepared by mixing a binder (ethyl cellulose) and an organic solvent (terpineol, texaneol).

The paste thus prepared was screen printed on a 6 "glass substrate, dried at 170 ° C. for 10 minutes, and calcined at 560 ° C. for 30 minutes. After baking, the glass thick film was formed to have a thickness of 20 μm. The state was evaluated and the results are shown in Table 2.

Permeability and bubble occurrence frequency by drying method Oven drying Spray drying Vacuum drying Assessment Methods Remarks Moisture content (%) 0.4 0.3 0.1 Moisture Meter 5 minutes at 10 g Transmittance (%) 69 77 82 UV-Vis 20㎛ thick film formation transmittance of 80% or more Bubble frequency (piece / mm ³ ) > 400 20 0 Optical micrograph (X400) Pore frequency: 0.03 pieces / mm ³ or less Pore size: 3 ~ 10㎛ Abnormal bubble U radish radish Optical micrograph (X400) Bubble size: more than 10㎛

As shown in Table 2, in the high temperature drying method, the bubble generation frequency is high due to the effect of Pb and B elution, while the vacuum pressure drying method, which is a low temperature drying method, has almost no bubble frequency and no abnormal bubbles are generated. I can see it.

Example 3

The secondary dry pulverized glass particles obtained in Example 1 were subjected to third wet pulverization at a circumferential speed of 13 m / sec using 1 zirconia beads in a 1.2 L bead mill to prepare a slurry having an average particle diameter of 1 탆.

Each sample was prepared by drying the slurry prepared by the third wet grinding by the drying method of Example 2. The dried samples were subjected to a calcination process according to the conditions shown in Table 3 below, and each sample was designated as Samples A to E. The calcining process was carried out in an alumina container laminated with the dried glass powder to 1cm or less and in a batch furnace for 2 hours at atmospheric temperature at 440 ℃. In the acid treatment, the third wet grinding was performed under the above conditions in a 2% nitric acid solution atmosphere.

division Sample A Sample B Sample C Sample D Sample E Execution condition Acid treatment × O × O O Drying method Vacuum reduced pressure drying Oven drying Spray drying Calcination O O × O O result Transmittance (%) 89 85 66 72 80 Bubble frequency 0 0 > 400 > 400 12 Abnormal bubble radish radish radish U radish

According to the method of manufacturing the glass frit powder for PDP paste of the present invention, it is possible to effectively control the particle size of 0.5 μm or less and the maximum particle size of 10 μm or more. Since it can be minimized, the dispersion and the flow rate become uniform during manufacturing as a PDP paste, so that the sintered state is uniform after partitioning or dielectric formation, and the reflectance and transmittance can be enhanced.

Further, according to the present invention, the above-described effect can be further enhanced by carrying out the calcination treatment in addition to the acid treatment during the wet grinding.

Claims (6)

In preparing glass frit powder for PDP paste, PbO, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , ZnO, BaO, TiO ₂ , ZrO ₂ , Bi ₂ O ₃ , CaO, MgO, CeO ₂ , Sb ₂ Injecting a glass raw material consisting of O ₃ into a platinum melting furnace and heating in a temperature range of 1,000 to 1,300 ℃ to produce a cullet; Primary dry grinding of the average particle diameter of the cullet using a ball mill or a disk mill in the range of 10 to 15 μm; Secondary dry grinding of the glass particles obtained above into a particle size of 1.5 to 2.5 μm with a dry grinding machine; Tertiary wet grinding of the glass particles obtained in the second grinding step to a particle size of 0.5 to 1.5 mu m; And drying the glass frit powder for PDP paste. The method of claim 1, wherein in the second dry grinding step, the glass particles are pulverized with a jet mill. The method for producing glass frit powder for PDP paste according to claim 1, wherein the third wet grinding step is performed with a bead mill. The method of claim 1, wherein the drying is carried out by vacuum drying under reduced pressure. The method for producing glass frit powder for PDP paste according to any one of claims 1 to 4, wherein the third wet grinding step is performed under a nitric acid solution atmosphere of 2% or less. 6. The method for producing glass frit powder for PDP paste according to claim 5, wherein the calcination step is further performed in an air atmosphere at a glass transition point region temperature of 350 to 550 캜 for at least 2 hours.