KR100782160B1 - Glass frit composition for PD barrier - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass frit composition for partition walls that does not contain a PbO component used in a plasma display panel (PDP), and has 40 to 50 wt% Bi ₂ O ₃ , 25 to 45 wt% ZnO, and 15 to 25 wt% B ₂ as main components. O ₃ as a _secondary component, BaO, K ₂ O, Al ₂ O ₃ And at least one selected from SrO is presented a glass frit composition for PD barrier ribs comprising 0.5 to 11wt%.

Description

Glass Frit Compositions for Barrier Ribs of PDP

1 is an electron micrograph of before and after etching of Example 9.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass frit composition for partition walls used in plasma display panels (PDPs), and more particularly, to a glass frit composition for PDP partition walls which does not contain a PbO component used as a main component and can be fired at low temperature.

Among the components of the display device of the PDP, the partition wall on the rear substrate is important for forming discharge cells coated with red (R), green (G), and blue (B) phosphors, determining pixels, and preventing inter-pixel mixing. Play a role. The required characteristics of the partition wall include the compactness and high strength (breaking toughness) of the partition wall, the coefficient of thermal expansion similar to that of the substrate glass, the high light reflectance, the high aspect ratio, and the low dielectric constant.

In recent years, research on bulkheads has been actively conducted in three aspects.

First, PbO-based glass used in the case of the Republic of Korea Patent Application Publication No. 10-2002-0077551 and the existing bulkhead is replaced with lead-free glass. The bulkhead materials of the early days of PDP are mainly glass of lead-borate composition of PbO-B ₂ O ₃ -SiO ₂ , which is applied to the environmental regulation by using PbO in excess of 60-80 wt%. In other words, electronic products containing PbO-containing materials have been used since 2006 and 2007, respectively (Restricting the use of hazardous substance) and WEEE (Waste electrical and electronic equipment). Directives will regulate the use of hazardous substances. For this reason, the development of lead-free glass compositions is urgent and many studies have been made.

Second is the study of the reactivity of fillers (fillers), pigments and mother glass added to improve the thermal, mechanical and functional properties of bulkheads. Many studies have been made on fillers suitable for conventional PbO-based glass compositions and are currently commercialized. However, according to the development of lead-free glass composition, it is also necessary to develop a suitable filler.

Third, as in the case of the Republic of Korea Patent Application Publication No. 10-2004-0010987, it is an improvement of the manufacturing method related to the pattern formation of the partition wall. In order to increase luminous efficiency, which is one of the disadvantages of PDP, various methods have been proposed in relation to the size of pitch cells in terms of cell shape and high definition. In the conventional sandblasting technique, various techniques have been studied to form high-definition barrier ribs in the existing sandblasting technique. However, the biggest alternatives are the formation of barrier ribs using an etching technique and photosensitive barrier ribs capable of forming patterns on their own. The bulkhead formation method includes a sandblasting method, a photosensitive paste method, and a chemical etching method, and is currently changing from a sandblasting method to a chemical etching method.

Until now, the technological development of PDP has focused on improving luminous efficiency, high quality and low price. As an alternative to PbO glass, the B ₂ O ₃ -ZnO-SiO ₂ system, which introduces B ₂ O ₃ and SiO ₂ as glass forming agents, has a glass transition point of more than 500 ° C and a softening point of 620 ° C. It is reported. Another composition has a P ₂ O ₅ has been investigated to a phosphate to step P ₂ O ₅ -ZnO-RO boundaries zero glass formation, and the introduction of the biggest problems in the additive of less than 10mol% to improve the water resistance of the phosphate-based glass The composition is being studied.

On the other hand, in terms of the formation process of the partition wall, the paste used for printing and table coating was mainly used, but the development of a technology for manufacturing a green sheet by thinly and densely tapening a doctor blade and then stacking a plurality of layers It is actively underway. After forming such a green sheet, an etching method is most commonly used to form a partition wall. In order to improve the efficiency and resolution of the PDP, efforts have been made to change the structure of the partition wall. As the size of the PDP increases, in order to improve or maintain the resolution, technologies for gradually decreasing or changing the width of the bulkhead are being actively developed.

The present invention has been made in view of the problems of the prior art, and the present invention solves the environmental pollution problem and the weight problem of the device when the PbO component is used, and at the same time, it is capable of low-temperature firing and has a high PDP. It is to provide a glass frit composition for a partition.

In order to achieve the above object, according to the present invention, 40 to 50 wt% Bi ₂ O ₃ , 25 to 45 wt% ZnO and 15 to 25 wt% B ₂ O ₃ as main components, BaO, K ₂ O, Al ₂ O as _secondary components ₃ And at least one selected from SrO is provided with a glass frit composition for PD barrier ribs comprising 0.5 to 11wt%.

In the present invention, the main components for forming glass include Bi ₂ O ₃ , ZnO, and B ₂ O ₃ , and these components form glass as a mesh forming agent, a mesh modifier, and an intermediate mesh modifier when forming glass. .

First of all, Bi ₂ O ₃ and B ₂ O ₃ may be mentioned as a network forming agent, and these components play the most important role in glass formation, and B ₂ O ₃ or ZnO is used as a network modifier and a middle fiber modifier. Contributes to the thermal properties of the glass and the chemical stability of the glass in terms of its properties. That is, the thermal properties and stability of the glass can be ensured by appropriately limiting the glass composition range.

Considering the thermal properties and stability of these glasses, the composition range proposed in the present invention is most preferred. In other words, if the amount of Bi ₂ O ₃ , B ₂ O ₃ , ZnO is different, it may not be possible to produce glass and may cause an increase in the glass transition point, and thus it may not be possible to obtain a dense sintered compact required by the partition wall.

In the present invention, Bi ₂ O ₃ is a main component for forming the glass and lowering the glass transition point, and the content thereof is preferably 40 to 50 wt%. If Bi ₂ O ₃ is less than 40%, the glass transition point tends to be high, so that firing is not possible at low temperatures, and if it is more than 50%, the glass is unstable and crystallization may occur during glass formation.

B ₂ O ₃ is essential as a forming component of glass, and its content is suitably 15 to 25% to play a role of lowering the glass transition point. If B ₂ O ₃ is less than 15%, the glass may become unstable and may cause crystallization during glass formation. In addition, when the partition is applied, the sintering property is lowered, making it difficult to obtain a compact partition. If it is more than 25%, the glass becomes more viscous and calcination at low temperature becomes impossible.

ZnO is a glass mesh modifier and therefore essential for lower glass transition points and as a component that induces sinterability and crystallization in partition applications. 25-41% of the content is suitable. If the content is less than 25%, the glass transition point is increased, and the sinterability is lowered and it is difficult to obtain a dense partition. When more than 41%, the stability of the glass is lost, resulting in crystallization during glass formation, the chemical properties of the glass are deteriorated, and many problems such as water resistance may be caused.

On the other hand, in the present invention, BaO, K ₂ O, Al ₂ O ₃ as a minor component And 0.5 to 11 wt% of at least one selected from SrO, and these components are closely related to the thermal properties of the glass, the etching characteristics and the stabilization of the glass, etc. in addition to the glass formation. Too many of these components, i.e. more than 11%, causes glass to become unstable, resulting in crystallization during glass formation, rise and fall of glass transition points, and rise in etching rate, and less than 0.5%. It may cause destabilization of the glass, an increase in the glass transition point, and a decrease in the etching rate.

Specifically, the BaO component is effective for heat resistance and increases the stability and compactness of the partition wall. Alkali metal oxides, such as K ₂ O, facilitate the softening point adjustment of the glass. Al ₂ O ₃ has the effect of widening the range of vitrification and increasing the stabilization of the glass.

On the other hand, when preparing the partition wall using the glass frit composition of the present invention, ZnO and Al ₂ O ₃ , which are ceramic fillers, are added in an amount of 15 to 20 wt% based on the total composition. The ceramic filler is added for the purpose of increasing the etching rate, improving the mechanical strength as the partition wall, and facilitating the patterning of the partition wall.

Specifically, ZnO preferably contains at least 10wt% as a component that induces crystallization of the glass to improve the etching rate, and Al ₂ O ₃ is It is good to act as a component to improve the strength of the partition to be produced and to include at least 5wt%.

Hereinafter, embodiments of the present invention will be described in detail.

1) Manufacture of glass frit

Glass was prepared by adding various oxides to a Bi ₂ O ₃ -ZnO-B ₂ O ₃ glass system. In the manufacture of glass, the mixture was subjected to wet ball milling for 12 hours using zirconia balls and ethanol to homogeneously mix the raw materials. Then dried at 150 ° C. for 12 hours. The dried powder was melted in an electric furnace using an alumina crucible at 1000-1300 ° C. for 1-3 hours. The furnace was cooled by furnace injection after melting for the production of bulk glass.

In order to observe the dissolution characteristics of the prepared glass, after polishing the surface with SiC abrasive paper, a sample having a homogeneous surface roughness was prepared by fine polishing the surface of the sample using a diamond paste (diamond paste 1㎛). The polished fired body was subjected to dissolution test in a dissolution test in a dissolution tester, and preheated distilled water to about 50 ° C. using a Teflon beaker and then heated at 45 ° C. using 0.1-1.0 wt% nitric acid (HNO ₃ ) solution. Dissolution test was carried out for 15 minutes at. Etch rate is a percentage of weight loss before and after etching.

In addition, thermal analysis (DTA) was performed to confirm the glass transition point of the prepared glass frit.

The above results are shown in Table 1.

Examples 1 to 8 shown in Table 1 has a glass transition point of 435 ~ 463 degrees, it can be confirmed that low-temperature firing of 550 degrees or less is possible. On the other hand, the measured etching rate was lower than the etching rate of the commercial material, but since this is not a partition of the composite, the etching rate of the mother glass, as shown in Table 1, preferably has a range of 0.1-0.3.

This is because the effect of the filler added for the strength of the partition wall has a larger etching rate.

In addition, BaO added in Bi ₂ O ₃ -ZnO-B ₂ O ₃ glass system lowers the glass transition point, and Al ₂ O ₃ serves to stabilize and prevent crystallization of glass, and in the case of K ₂ O Lowering the advantage, SrO also has the effect of lowering the glass transition point.

sample Bi ₂ O ₃ ZnO B ₂ O ₃ BaO K ₂ O SrO Al ₂ O ₃ Tg (℃) Etch Rate (%) Example 1 41.5 31 17 10 0.5 436 0.1 Example 2 41.5 31 17 10 0.5 449 0.3 Example 3 41.5 36 17 5 0.5 440 0.1 Example 4 41.5 36 17 5 0.5 451 0.3 Example 5 41.5 41 17 0.5 455 0.3 Example 6 46.5 35 18 0.5 463 0.1 Example 7 50 27 21 1.5 0.5 460 0.1 Example 8 50 33 15 1.5 0.5 435 0.1

2) Manufacture of PDP Bulkhead

Example 6 of the above composition was selected as the mother glass, and in order to manufacture a partition wall, ceramic fillers ZnO (d ₅₀ : 1 micro) and Al ₂ O ₃ (d ₅₀ : 1.5 micro) were mixed in different contents. Compounding conditions are shown in Table 2.

The blended glass frit was mixed through a ball milling process using a zirconia ball for 12 hours, and then the glass frit was dried at 150 degrees for 24 hours. The mixture of glass frit and ceramic fillers was compression molded into disc form at a pressure of about 2 ton / cm ² . Thereafter, the composite was manufactured through a calcination process at 550 ° C. for 30 minutes. Subsequently, the physical properties (hardness and modulus of elasticity) for each example were measured and shown in Table 2 by a method commonly used in the art.

As shown in Table 2, the strength of the partition wall was different depending on the mixing ratio of the glass frit and the filler. This tendency is also similar to the change in modulus of elasticity. Examples 9 and 10 were found to be equal or higher compared to the mechanical properties of commercial bulkheads. Therefore, according to the present invention it can be seen that the partition wall material having a filler content of about 15 to 20wt% is an optimal condition for the application. According to the present invention, as the amount of filler increases (more than 20wt%), the hardness and elastic modulus decrease due to the increase of porosity in the matrix, thereby acting as a factor that inhibits the mechanical properties of the partition wall.

sample Glass frit (wt%) (Example 6) Filler (wt%) Vickers Hardness (MPa) Modulus of elasticity (GPa) Remarks ZnO Al ₂ O ₃ Example 9 85 10 5 460 + 20 85 O Example 10 80 15 5 450 84 O Comparative Example 1 75 20 5 270 71 X Comparative Example 2 80 10 15 280 81 X Comparative Example 3 75 15 10 260 76 X Comparative Example 4 70 20 10 200 70 X Comparative Example 5 Commercial bulkhead 490-340 80-60 -

Note: X is defective, O is passed.

3) Dissolution test

In order to investigate the reactivity of the glass frit and filler, the exothermic reaction temperature is shown in Table 3 by thermal analysis. At this time, the reaction was measured according to the change of time in an isothermal experiment maintained for 30 minutes after reaching 550 degrees at 10 degrees per minute rise. In addition, in order to observe the dissolution characteristics of the prepared glass, the surface was polished with SiC abrasive paper, and then the surface of the sample was finely polished using diamond paste 1㎛ to prepare a test piece having a uniform surface roughness. The polished fired body was subjected to dissolution test in a dissolution test in a dissolution tester, and preheated distilled water to about 50 ° C. using a Teflon beaker and then heated at 45 ° C. using 0.1-1.0 wt% nitric acid (HNO ₃ ) solution. Dissolution test was performed for 20 minutes at.

Referring to Table 3, it can be seen that in Example 15 and Example 17, crystallization did not occur, whereas in Example 16 and Example 18, crystallization occurred. It is expected from this that when the ZnO filler is added, the glass and the filler react to form a crystal phase around the filler. After firing the mixture of mother glass and filler, the crystal phases were analyzed by XRD, and two crystal phases appeared. One of them is the reaction phase of the mother glass with ZnO filler (Zn ₃ B ₂ O ₆ or ZnB ₂ O ₄ ) and the other is the phase produced from the mother glass (Zn ₃ B ₂ O ₆ or Bi ₃ B ₅ O ₁₂ )to be. However, no phase produced by reaction with Al ₂ O ₃ was found.

This result is the same as the phenomenon shown in Table 3. These crystal phases affect the etching mechanism of the acid etching process for forming the partition walls. That is, the remaining glass portion is eluted first on the surface of the glass frit to expose the filler (Al ₂ O ₃ ) and the crystal phase. Subsequently, the filler (Al ₂ O ₃ ) is released and elution occurs in the crystal phase. As a result, the mother glass part is revealed again from the surface, and elution takes place again at the position where the filler (Al ₂ O ₃ ) was removed. That is, the phenomenon in which the partition wall is etched can be explained as the crystal phase generated by the reaction of the ZnO filler and the glass with the etching in the glassy part is eluted to fall off around the filler. From this fact, it can be seen that the process by acid etching can be more efficiently achieved by adding a ZnO filler for the production of partition walls to the Bi ₂ O ₃ glass composition.

This fact can also be seen from the accompanying FIG. 1, which shows the composition of Example 9 in 0.5% HNO _3. It is a photograph of the surface etched at 45 degreeC by the solution. It can be seen from FIG. 1 that the unreacted Al ₂ O ₃ filler is released by elution of a new crystal phase generated by reaction with ZnO.

Example Composition (wt%) Glass transition point Tg (℃) Exothermic reaction (peak temperature Tp (℃))  Example 15 Glass frit (100) 463 -  Example 16 Frit (90) + Filler (ZnO) (10) 463 565  Example 17 Frit (90) + filler (Al ₂ O ₃ ) (10) 463 -  Example 18 Frit (80) + Filler (ZnO (10) + Al ₂ O ₃ ) (10) 463 592

* The number in parentheses is the weight ratio

As described above, the present invention provides the following effects.

First, the glass frit having a composition of 40 to 50 wt% Bi ₂ O ₃ , 25 to 41 wt% ZnO, and 15 to 25 wt% B ₂ O ₃ has thermal properties capable of low temperature firing as a PD barrier composition for acid etching.

Second, the partition wall material was added to a mixed amount of 15~20wt% of ZnO and Al ₂ O ₃ as a filler in the composition of the lead-free Bi ₂ O ₃ system is the physical properties of the material equal to prepare commercial partition bars or having superior hardness and modulus of elasticity Indicates.

Third, the partition material in which ZnO is added as a filler to the lead-free formation of Bi ₂ O ₃ system has the effect of being easily etched by nitric acid in the etching process.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (3)

40 to 50 wt% Bi ₂ O ₃ , 25 to 41 wt% ZnO and 15 to 25 wt% B ₂ O ₃ as main components, and 0.5 to 11 wt at least one selected from BaO, K ₂ O, Al ₂ O ₃ and SrO as secondary components 80 to 85 wt% of glass frit comprising%; A glass frit composition for PD barrier ribs comprising 15 to 20 wt% of a filler composed of ZnO and Al ₂ O ₃ . delete The method of claim 1, ZnO of the filler is at least 10wt%, Al ₂ O ₃ of the filler is Glass frit composition for PD barrier ribs, characterized in that at least 5wt%.

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