JPH1111978A - Barrier rib forming material for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material capable of yielding a calcined body which is usable in the form of a green sheet and is stable in a blast rate by compounding high softening glass powder and low softening glass powder having softening points each in a specific range and refractory filler powder at a specific ratio and incorporating a binder into this mixture. SOLUTION: This material is used to form barrier ribs for segmenting many gas discharge parts held by the glass substrates of rear surface and front surface required for a plasma display and more particularly AC type plasma display. The binder is incorporated into the inorg. components consisting of 50 to 80 wt.% high softening glass powder having a softening point of 500 to <600 deg.C, 5 to 40 wt.% low softening glass powder having the softening point of 300 to <400 deg.C and 5 to 20 wt.% refractory filler powder. This material has a suitable strength and blast rate at the time of calcining, has an excellent mountability to the glass substrates and allows the formation of the dense ribs having high mechanical strength at the time of normal firing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for forming a barrier rib of a plasma display device (PDP), and more particularly to an AC material.
The present invention relates to a barrier rib forming material for a plasma display device.

[0002]

2. Description of the Related Art In general, as shown in FIG. 1, an AC type plasma display apparatus has ribs called barrier ribs for dividing a space between a rear glass substrate 1 and a front glass substrate 2 into a number of gas discharge parts. The partition wall 3 is formed.

[0003] As one method of forming such ribs, a sand blast method is known.

In the sand blast method, a paste containing a glass powder and a refractory filler powder is solid-coated on a substrate,
Subsequently, after removing portions other than the ribs by sandblasting through a mask, firing is performed at 500 to 600 ° C. However, in this method, the paste must be repeatedly printed about 10 times to form ribs having a predetermined height (usually 150 to 200 μm).
Very inefficient.

[0005]

Therefore, instead of forming a paste layer by printing, a method of forming a barrier rib material into a green sheet having a predetermined thickness in advance and pressing the green sheet on a substrate has been studied.

When a rib is formed using a green sheet, the amount of the binder contained is larger than the amount of the paste, and the blasting agent is repelled and cut even when sand blasting is performed on the green sheet pressed on the substrate as it is. Because of this, the binder is removed before blasting. However, when the binder is removed, the mechanical strength of the sheet is significantly reduced, and the sheet is likely to collapse when the mask is attached. Therefore, it has been proposed to increase the mechanical strength of the sheet by calcining at 400 to 500 ° C. after removing the binder. However, in the case of conventional materials, if the conditions of the calcining change even slightly, the cutting rate (blast rate) at the time of sand blasting is changed. ) Fluctuates. For this reason, when preliminarily firing a large-area substrate using a large-scale firing furnace having a large temperature difference in the furnace, it is difficult to form uniform ribs over the entire surface of the substrate.

An object of the present invention is to provide a barrier rib forming material for a plasma display which can be used in the form of a green sheet and can obtain a calcined body having a stable blast rate.

[0008]

As a result of various studies, the inventors of the present invention have emphasized the importance of maintaining the shape of the barrier rib in the DC plasma display apparatus. There is no outgassing, that is, the denseness of the barrier ribs is regarded as important, so that the ratio of the glass powder needs to be higher than the refractory filler powder, and a predetermined amount of the low softening point glass powder in the rib forming material. It has been found that the above-mentioned object can be achieved by the addition.

That is, the barrier rib forming material for plasma display of the present invention has a softening point of 50 to 80% by weight of a glass powder having a high softening point of 500 ° C. or more and less than 600 ° C. and a softening point of 3%.
Low softening point glass powder of not less than 00 ° C and less than 400 ° C 5 to 40
The composition is characterized in that it contains an inorganic component composed of 5% by weight and 5 to 20% by weight of a refractory filler powder, and a binder.

[0010] The high softening point glass powder is a component that softens and flows during the main firing to form densely sintered ribs having high mechanical strength. The reasons for limiting the softening point and content of the high softening point glass powder as described above will be described below. When the softening point of the high softening point glass powder is lower than 500 ° C., the glass is excessively softened and flowed, and the shape of the rib cannot be maintained. When the softening point exceeds 600 ° C., the fired body does not sinter densely, and a high strength rib is obtained. Can not be. If the glass having a high softening point is less than 50% by weight, the fired body is not densely sintered, and a rib having high mechanical strength cannot be obtained. I can't keep it. Although not particularly limited in composition of the glass powder used, PbO 50-70% by weight%, B ₂ O ₃ 0.1~30
_{%, SiO 2 1~30%, Al} 2 O 3 0~5%, Z
nO 0 to 20%, it is preferable to use those having a composition of TiO ₂ 0 to 5%.

[0011] The low softening point glass powder is a component for softening and flowing at the time of calcination to bond other powders together to obtain a calcination body having appropriate strength. The reasons for limiting the softening point and content of the low softening point glass powder as described above will be described below. When the softening point of the low softening point glass powder is lower than 300 ° C. and when the content of the low softening point glass is more than 40% by weight, the calcined body is densely sintered and the mechanical strength becomes too high, and sand blasting is performed. Makes cutting difficult. If the softening point is 400 ° C. or more, or if it is less than 5% by weight, the mechanical strength of the calcined body cannot be maintained, and the calcined body collapses when a mask is attached, or the blast rate of the calcined body becomes unstable. The composition of the low softening point glass powder to be used is not particularly limited.
_{80~90%, B 2 O 3 10~15} %, SiO 2
_{0.1~2%, Al 2 O 3 0~2} %, ZnO 0~5
%, It is preferable to use those having a composition of Bi ₂ O ₃ 0~5%.

[0012] The refractory filler powder is a component that becomes a rib aggregate. If the content of the refractory filler powder is less than 5% by weight, the glass will flow too much during calcination and the blast rate will be small. On the other hand, when the content is more than 20% by weight, the fired body is not densely sintered, and the mechanical strength is reduced. As the refractory filler powder, alumina, zircon, zirconia, titania, lead titanate, cordierite, mullite and the like can be used. If necessary, Cu-Cr based,
Up to 20% by weight of an inorganic oxide pigment such as Fe-Mn may be contained.

As the binder, acrylic resin, butyral resin, polyvinyl alcohol and the like can be used.
Among them, acrylic resin is preferable. The amount of the binder added is 10 to 20% by weight based on 100% by weight of the inorganic component.
It is preferred that

[0014] The material of the present invention, other than the above components,
Components such as a plasticizer can be contained.

The plasticizer is a component that enhances the flexibility of the sheet and imparts self-adhesiveness. Examples thereof include dibutyl phthalate, dioctyl phthalate, butylbenzyl phthalate, and dimethyl phthalate. The amount of the plasticizer added is preferably 1 to 10% by weight based on 100% by weight of the inorganic component.

Next, a method for manufacturing a green sheet using the material of the present invention and a method for forming a barrier rib using the green sheet will be described.

First, a glass powder having a high softening point in the above ratio,
A low softening point glass powder and a refractory filler powder are prepared. Next, a binder, a solvent, and if necessary, a plasticizer and the like are added to these powders, and kneaded using a ball mill or the like. Then, it is formed into a sheet by a doctor blade method and dried to obtain a green sheet having a sheet thickness of 100 to 400 μm.

In order to form a barrier rib using the green sheet thus produced, first, the green sheet is thermocompression-bonded to a substrate with a roller or the like, and then the green sheet is formed.
The binder is removed from the green sheet by heating to 400 ° C. Subsequently, after pre-baking at a temperature of 400 to 500 ° C., a mask is attached, and parts other than the ribs are removed by sandblasting. Thereafter, main firing is performed at 500 to 600 ° C. to form barrier ribs.

[0019]

In the conventional calcination of the material, the glass powders are combined with each other and the glass powder and the refractory filler powder by utilizing the slight softening of the glass powders. For this reason, even if the conditions of the pre-sintering are slightly changed, a large difference occurs in the degree of softening of the glass powder, the influence on the bonding force between the powders is increased, and the blasting of the pre-sintered body becomes unstable.

On the other hand, the rib forming material of the present invention is:
Since the other powders are bonded to each other using the softening flow of the low softening point glass powder, even if the conditions of the pre-baking are slightly changed, the flowability of the low softening point glass is not so affected, and as a result, stable brass Is obtained.

[0021]

EXAMPLES Hereinafter, a material for forming a barrier rib for a plasma display according to the present invention will be described based on examples. Table 1 shows the high softening point glass powders (samples A to C) used in the examples and comparative examples of the present invention, and Table 2 shows the low softening point glass powders (samples a to c) used in the examples of the present invention. Each is shown. Tables 3 and 4 show examples of the present invention (sample N
o. 1 to 6) and Comparative Example (Sample No. 7).

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

Sample No. 1 to 6 were prepared as follows. First, a glass powder having a high softening point, a glass powder having a low softening point and a refractory filler powder were prepared in the proportions shown in the table.
3% by weight of butylbenzyl phthalate and 25% by weight of a solvent were added and kneaded in a ball mill. Then, it was formed into a sheet by a doctor blade method and dried to obtain a sample (green sheet). The sheet thickness of the obtained sample was about 200 μm.

Sample No. Sample No. 7 was prepared in the same manner as described above except for using a high softening point glass powder and a refractory filler powder.

Next, with respect to the obtained sample, the stability and the denseness of the blasting of the calcined body were evaluated.

As is clear from the table, the sample No. In Examples 1 to 6, the width of the temperature range in which the rate of change of the blast rate was within 5% was 20 ° C. Also, the denseness was good. On the other hand, the sample No. 7 had a temperature range of only 5 ° C. Moreover, the denseness was bad.

Subsequently, after sandblasting each sample of the preliminarily fired example, the main firing was performed at the firing temperature shown in the table. As a result, a rib having a height of about 180 μm was uniformly formed on the entire surface of the substrate. It was confirmed that.

The blast rate stability was evaluated as follows. First, each sample was thermocompression-bonded on a glass substrate, and then heated at 350 ° C. for 20 minutes to remove the binder. Subsequently, after calcination at 450 ° C. for 30 minutes, the blast rate was measured. Further, the blast rate was measured while changing the calcination temperature, and the temperature range of the calcination temperature range in which the rate of change with respect to the blast rate was within 5% was determined. The denseness was evaluated by applying an oil-based ink to the fired glass film and then performing an ink wiping test for wiping with an alcohol. In this test, the ink having good denseness was wiped off with good ink, and the ink having poor denseness was hardly wiped off because the ink was soaked.

[0032]

According to the barrier rib forming material for plasma display of the present invention, since the blasting rate of the obtained pre-fired body is stable, even when a large-area substrate is pre-fired in a large-scale firing furnace, the ribs are uniformly formed. Can be formed. Therefore, it is suitable for mass production and can be adapted to large size, and is suitable as a green sheet material for forming ribs of a plasma display device.

Claims (5)

[Claims] 1. A high softening point glass powder having a softening point of 500 ° C. or more and less than 600 ° C. and a softening point of 300 ° C.
5 to 40% by weight of low softening point glass powder having a temperature of not less than 400 ° C.
A barrier rib forming material for plasma display, comprising: an inorganic component comprising: a refractory filler powder and 5 to 20% by weight; and a binder. 2. The high softening point glass powder contains PbO in weight%.
_{50~70%, B 2 O 3 0.1~30} %, SiO 2
_{1~30%, Al 2 O 3 0~5} %, ZnO 0~2
_{2. The} barrier rib forming material for a plasma display according to claim 1, wherein the material has a composition of 0% and 0 to 5% of TiO2. 3. The low-softening point glass powder contains PbO
_{80~90%, B 2 O 3 10~15} %, SiO 2
_{0.1~2%, Al 2 O 3 0~2} %, ZnO 0~5
%, Barrier rib forming material for a plasma display according to claim 1, characterized in that it has a composition of Bi ₂ O ₃ 0~5%. 4. The barrier rib forming material for a plasma display according to claim 1, which is supplied in the form of a green sheet. 5. The barrier rib forming material for a plasma display according to claim 4, wherein the sheet has a thickness of 100 to 400 μm.