KR101309814B1 - Composition for preparing electrode and plasma display panel comprising electrode prepared terefrom - Google Patents

Abstract

The composition for forming an electrode of the present invention comprises (a) a conductive powder, (b) an organic binder and (c) a glass frit, wherein the glass frit (c) is an alkali free glass frit containing no (c1) alkali; And (c2) a low alkali glass frit having an alkali content of greater than 0 and 3% by weight or less, and (d) a solvent. The bus electrode of the plasma display panel to which the electrode forming composition is applied has improved yellowing and edge curl.

Description

Plasma display panel comprising a composition for forming an electrode and an electrode formed therefrom {COMPOSITION FOR PREPARING ELECTRODE AND PLASMA DISPLAY PANEL COMPRISING ELECTRODE PREPARED TEREFROM}

The present invention relates to a plasma display panel comprising a composition for forming an electrode and an electrode formed therefrom. More specifically, the present invention relates to an electrode forming composition in which yellowing is eliminated by introducing a specific glass frit, and a plasma display panel including an electrode formed therefrom.

Plasma Display Panels (PDPs) are flat display devices that display images or information using light emission by gas discharge. The PDP secures a discharge space partitioned by partition walls on the rear glass substrate, and an address electrode is introduced into the discharge space. The front glass substrate is opposedly introduced onto the back glass substrate, and the transparent dielectric layer is interposed on the front glass substrate. A transparent electrode and a bus electrode as display electrodes are disposed on the front glass substrate so as to face the dielectric layer so as to intersect with the address electrode.

The structure of the plasma display panel (PDP) is usually a glass substrate called a front substrate, in which a transparent electrode (holding electrode) and a bus electrode are covered with a dielectric layer, and a glass called a back substrate having a cell structure composed of an address electrode, a dielectric layer, a partition wall, and a phosphor. It includes a substrate, it has a form arranged facing each other so that the electrodes on both sides orthogonal. Light emission is performed by applying a voltage between the electrodes on both sides, generating a discharge phenomenon in the cell, and exciting the phosphor in the cell by the generated ultraviolet rays. The image obtained by the combination of each of the red cyan light emitting (RGB) cells that are emitted by the structure of the panel is recognized behind the surface on which the electrode of the front substrate is formed. For this reason, a method of forming a black electrode between the transparent electrode and the bus electrode has been known as a method of suppressing recognition from the back of the bus electrode on the front substrate corresponding to the display surface in order to improve the quality of the displayed image. .

Until now, various methods for suppressing yellowing of the glass substrate have been proposed. In the case of bus electrode development, it attempted to solve yellowing by suppressing the under cut of the black layer as much as possible and increasing the blackness of the composition for forming the black layer itself, but fundamentally failed to prevent Ag + diffusion. It was. Japanese Patent Laid-Open No. 2005-7010168 attempts to improve yellowing by minimizing the alkali content in the glass substrate. The less the alkali component, the more effective the yellowing prevention, but there is a problem that the edge curl occurs. The occurrence of edge curl is a problem of degrading product quality because the breakdown voltage of the transparent dielectric layer introduced on the bus electrode is drastically lowered, which may cause mis-discharge during discharge or damage to the dielectric constant due to discharge.

In Japanese Patent Laid-Open No. 10-255669, the yellowing was improved by removing the reducing layer present on the surface by polishing the surface of the glass substrate. In addition, Japanese Patent Application Laid-Open No. 2001-213634 includes a halogen group element (F, Cl, Br, I), etc., which can be combined with the Ag + theory, to prevent Ag colloid from being formed. The above methods have tried to improve the glass substrate, but due to the problems of mass production or price is not a realistic solution.

An object of the present invention is to provide a composition for forming an electrode that does not generate edge curl while the yellowing phenomenon is improved.

Another object of the present invention is to provide a composition that can minimize the occurrence of undercut.

Still another object of the present invention is to provide a bus electrode of a plasma display panel formed of the composition for forming an electrode.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical subjects which are not mentioned can be understood by those skilled in the art from the following description.

One aspect of the present invention relates to a composition for forming an electrode. The electrode forming composition comprises (a) a conductive powder, (b) an organic binder, (c) a glass frit, and d) a solvent, wherein the glass frit (c) is an alkali-free glass containing no (c1) alkali. Frit; And (c2) a low alkali glass frit having an alkali content of greater than 0 and 3% by weight or less.

In embodiments, the glass frit (c) may have a ratio of (c1) non-alkali glass frit and (c2) low alkali glass frit 1: 1-5.

The composition may include (a) 40 to 90% by weight of the conductive powder, (b) 0.1 to 20% by weight of the organic binder, and (c) 1 to 20% by weight of the glass frit and d) a solvent.

The conductive powder (a) is silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), tin (Sn) ), Lead (Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo), nickel (Nickel) and ITO (indium) Tin oxide) may include one or more conductive powders selected from the group consisting of.

The organic binder (b) may include at least one of a urethane (meth) acrylate resin and an acrylic resin.

Another aspect of the present invention relates to a plasma display panel including an electrode formed from the composition for forming an electrode.

The present invention has the effect of providing an electrode forming composition and a plasma display panel formed from the composition, which can minimize the occurrence of undercut, while the yellowing phenomenon is not generated edge curl.

1 illustrates a bus electrode of a plasma display panel according to an exemplary embodiment of the present invention.
2 is a measurement graph showing an edge profile of a bus electrode of a plasma display panel according to an exemplary embodiment of the present invention.

The composition for electrode formation of this invention contains (a) conductive powder, (b) organic binder, (c) glass frit, and d) solvent.

(a) conductive powder

As the conductive powder used in the present invention, both conductive organic and inorganic materials may be used. For example, silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), tin (Sn), lead ( Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo), nickel (Nickel) or ITO (indium tin oxide) These may be used, and these may be used alone or in combination of two or more, or may be used as an alloy. In addition, it may be used in the form in which another metal is coated on one of the metals. Among these, silver powder may be preferably used.

The conductive powder may be spherical, needle-like, plate-like, amorphous, and the like. It is preferable that the double particle shape is spherical because spherical particles have properties superior to plate-like or amorphous in terms of filling rate and ultraviolet transmittance.

The average particle diameter (D50) of the conductive powder is 0.01 to 10 µm, preferably 0.1 to 5 µm, more preferably 0.5 to 3 µm, and most preferably 1 to 2.5 µm in consideration of the used film thickness.

The content of the conductive powder is 40 to 90% by weight, preferably 45 to 80% by weight, more preferably 50 to 75% by weight of the total composition. In the above range, the electrode may have sufficient conductivity, the discharge voltage may not increase, and problems such as pinholes, cracks, and short circuits of the electrode may not occur during the exposure and development processes.

(b) organic binder

In the present invention, the organic binder serves to disperse and bond the conductive material and the glass frit forming the electrode, and to provide adhesion to the glass substrate until printing and baking after drying.

The organic binder may include at least one of a urethane (meth) acrylate resin and an acrylic resin.

In an embodiment, the urethane (meth) acrylate resin may be a copolymer obtained by copolymerizing a glycol having a bifunctional or trifunctional hydroxyl group, a bifunctional or trifunctional isocyanate compound, and a (meth) acrylic monomer having a hydroxyl group and a vinyl group. have.

The urethane (meth) acrylate resin may have a weight average molecular weight in the range of 1,000 to 100,000 g / mol, preferably in the range of 5,000 to 40,000 g / mol.

In an embodiment, the acrylic resin may be a copolymer obtained by copolymerizing at least one member selected from the group consisting of (meth) acrylic acid, (meth) acrylic acid alkyl ester, acrylonitrile, styrene, and glycidyl (meth) acrylate. However, it is not limited to these. The weight average molecular weight of the acrylic resin may be 5,000 to 50,000 g / mol.

The organic binder may be used as an organic binder solution dissolved in a solvent.

The content of the organic binder is 0.1 to 20% by weight, preferably 0.3 to 15% by weight of the total composition on a solids basis. After preparing the composition for forming the electrode in the above range can maintain a suitable viscosity, and can maintain the adhesive strength with the glass substrate after printing, drying, it is possible to form a high-resolution pattern. In addition, problems such as cracking, opening, and pinhole generation of the electrode during the firing process do not occur.

When the urethane (meth) acrylate resin and the acrylic resin are mixed as the organic binder, the urethane (meth) acrylate resin and the acrylic resin are 5:95 to 50:50, preferably 10:90 to 45 in the whole organic binder. It may be included in the weight ratio of: 55, more preferably 15:85 to 30:70. It is excellent in adhesion with the substrate in this range, does not generate undercut and edge curl, and can keep the resistance low.

The organic binder is a styrene resin, a novolak resin, a polyester resin, a water-soluble cellulose resin, a polyvinyl alcohol resin, an epoxy resin, a melamine resin and a polyvinyl butyral resin, in addition to the urethane (meth) acrylate resin and the acrylic resin. It may further comprise one or more selected from the group consisting of.

(c) glass frit

The glass frit may induce an effect of improving the adhesion between the conductive particle powder and the lower substrate during the firing process and softening during sintering to lower the firing temperature.

In the present invention, the glass frit (c) is an alkali-free glass frit containing no (c1) alkali; And (c2) low alkali glass frits having an alkali content of greater than 0 and 3% by weight or less. Here, "alkali free frit free of alkali" means that the oxides of the Group I metals of the periodic table, such as Na ₂ O, K ₂ O, and Li ₂ O, are not substantially contained. In addition, the low alkali glass frit having an alkali content of more than 0 wt% and 3 wt% or less contains oxides of Group I metals such as Na ₂ O, K ₂ O, and Li ₂ O at less than 3 wt% of the total glass frit. It means.

In a specific embodiment, the glass frit (c) has a ratio of (c1) alkali free glass frit to (c2) low alkali glass frit: 1: 1-5, preferably 1: 1.5-4.5, more preferably 1: 2 Can be ~ 4. In this range, it is possible to minimize yellowing and improve edge curl by preventing diffusion and reduction of Ag + ions that cause yellowing in the above range.

Preferably, the glass frit has a softening point of 400 ° C. to 550 ° C. In the above range, the conductive particles have good sintered densities and may have low resistance characteristics.

In addition, the average particle diameter (D50) of the glass frit may be 0.5 to 5 ㎛, preferably 0.7 to 3 ㎛. Pinhole failure does not occur in the above range.

The content of the glass frit is preferably contained in 1 to 20% by weight, preferably 2 to 15% by weight, more preferably 3 to 10% by weight of the total composition. It is excellent in the adhesive force of the conductive powder and the glass substrate in the above range, there is no fear of resistance increase.

(d) solvent

As the solvent that can be used in the conductive composition of the present invention, an organic solvent having a boiling point of 120 ° C. or more that can be used in general may be used. In one embodiment, methyl cellosolve, ethyl cellosolve, butyl cellosolve, aliphatic alcohol, α-terpineol, β-terpineol, Dihydro-terpineol, Ethylene Grycol, Ethylene glycol mono butyl ether, Butyl Cellosolve Acetate, Texanol, etc. may be used. May be, but is not necessarily limited thereto. These can be used individually or in mixture of 2 or more types.

The content of the solvent will vary depending on the specific application, it may be easy to control the viscosity by adjusting the amount of the solvent. In embodiments it may be used in 5 to 50% by weight of the total composition.

In embodiments, the conductive composition may further include conventional additives as necessary to improve flow characteristics, process characteristics, and stability. The additive may include at least one plasticizer, a dispersant, a viscosity stabilizer, an antifoaming agent, a pigment, an ultraviolet stabilizer, an antioxidant, a thermal polymerization inhibitor, a coupling agent, and the like. These are all known enough to be commercially available to those of ordinary skill in the art, so specific examples and descriptions thereof will be omitted.

Another aspect of the present invention relates to a plasma display panel including an electrode formed from the composition for forming an electrode.

In a specific embodiment, a lower black layer electrode may be formed between an upper white layer electrode formed by the composition for forming an electrode and a lower ITO transparent electrode, thereby forming a two-layer bus electrode. The black paste for the black layer electrode contains black pigment. The black layer electrode may be formed by a black paste including a conductive material, an organic binder, a glass frit, and a black pigment, wherein the glass frit of the black paste is about 10 ° C. to 100 ° C. as compared to the glass frit of the conductive paste. Glass frits with low softening points can be used.

A black paste is applied and dried on the front glass substrate on which the transparent electrode is formed to form a black electrode layer, and the electrode forming composition of the present invention is coated and dried on the black electrode to form a white electrode layer, followed by exposure, development and A bus electrode having a two-layer structure can be manufactured through the step of firing.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Example

The specifications of each component used in the following Examples and Comparative Examples are as follows:

(a) Conductive powder: Silver (Ag) powder (Dowa / 5-11F) having an average particle diameter (D50) of 2.5 µm was used.

(b) organic binder

(b1) Acrylic resin: poly (methyl methacrylate-co-methacrylic acid) (Cheil Industries / OV5300) was used.

(b2) Urethane (meth) acrylate resin: Cytec EB9260 was used.

(c) glass frit

(c1) Glass frit with 0% alkali content (LF6007, Particle)

(c2) Glass frit with 2% alkali content (LF6106, Particle)

(c3) Glass frit with 4% alkali content (BF101D2, Particle)

(c4) Glass frit with 6% alkali content (BF1010D, Particle)

(d) Solvent: 2,2,4-trimethyl-1,3-pentanediol mono-isobutyrate (Eastman) was used.

Example  1 to 6 and Comparative Example  1-5

Each of the above components was mixed to proceed three passes using a ceramic three-roll mill to prepare a composition for forming an electrode.

After forming the ITO transparent electrode 20 on the front glass substrate 10 of the PDP as shown in FIG. 1, a black paste for the black layer electrode 30 is prepared on the transparent electrode 20. It was. The black paste was printed on a glass substrate (PD200) 7 × 7 cm using ST6500A (Tg = 410 ° C.) of Cheil Industries, and dried at 110 ° C. for 20 minutes. The electrode forming compositions prepared according to the composition ratios of Table 1 were printed in a size of 7 × 7 cm at the center of the black paste printed substrate using Sus 325 mesh, respectively, and dried at 110 ° C. for 20 minutes. The electrode forming composition is prepared for the white layer electrode 40 formed on the black layer electrode 30 as shown in FIG. After exposing the dried specimens with energy of 300mJ, they were developed with a developer of sodium carbonate 0.3% concentration to form electrode patterns of 50cm in length, 70㎛ in width and 200㎛ spacing between patterns, and then fired three times. It was. Blackness and edge curl were measured with the following method on the prepared sample.

(1) Blackness: The b * value indicating the yellowness level of the sample prepared above was measured using a color difference meter CM2600D.

(2) Edge curl: Edge curl was measured for the electrode pattern of 70 micrometers of line widths using the apparatus which measures the pattern profile like Tencor (P10 Profiler). Edge curl was evaluated by measuring the height of the pattern edge protruding sharply higher than the thickness of the electrode as shown in FIG.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 (a) conductive powder 63 63 63 63 63 63 63 (b) organic binder (b1) 10 10 9 9 9 9 10 (b2) - - 3 3 - 3 - (c) glass frit (c1) 2 One One 4 - - - (c2) 2 3 3 - 4 - - (c3) - - - - - 4 - (c4) - - - - - - 4 d) solvent 23 23 21 21 21 21 23 Blackness b * value
(Yellow value) Firing once 1.9 1.9 1.8 1.6 2.2 2.7 3.0 Firing 2 times 2.1 2.1 2.0 1.6 2.7 3.5 3.8 Firing 3 times 2.2 2.2 2.0 1.7 3.1 4.0 4.5 Edge curl (μm) 4 3 One 6 3 3 3

As shown in Table 1, Examples 1 to 3 have excellent edge curl, and it can be seen that yellowing hardly occurs even after repeated firing. In particular, in Example 3, in which the urethane acrylate was applied to the binder, yellowing hardly occurred, and the edge curl also maintained a low value. On the contrary, in Comparative Example 1, yellowing did not occur, but the edge curl was high, and in Comparative Examples 2 to 4, the edge curl was good but yellowing occurred.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

10 glass substrate 20 transparent electrode
30: black layer electrode 40: white layer electrode

Claims (9)

(a) a conductive powder, (b) an organic binder, (c) a glass frit, and (d) a solvent, wherein the glass frit (c) comprises (c1) an alkali free glass frit free of alkali; And (c2) a low alkali glass frit having an alkali content of more than 0 and 3 wt% or less, wherein the (c1) alkali free glass frit containing no alkali and (c2) a low alkali glass having an alkali content of more than 0 and 3 wt% or less. The ratio of frit is 1: 1-5, The composition for electrode formation characterized by the above-mentioned.
delete According to claim 1, wherein the composition for forming the electrode is (a) 40 to 90% by weight of the conductive powder, (b) 0.1 to 20% by weight of the organic binder and (c) 1 to 20% by weight and (d) the residual amount of the solvent Electrode composition for forming comprising a.
The method of claim 1, wherein the conductive powder (a) is silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum ( Al), tin (Sn), lead (Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo), nickel ( Nickel) and ITO (indium tin oxide) composition for forming an electrode, characterized in that it comprises at least one conductive powder selected from the group consisting of.
The composition for forming an electrode according to claim 1, wherein the organic binder (b) comprises at least one of a urethane (meth) acrylate resin and an acrylic resin.
The composition of claim 1, wherein the organic binder (b) comprises a urethane (meth) acrylate resin and an acrylic resin in a weight ratio of 5:95 to 50:50 in the whole organic binder.
The method of claim 5, wherein the organic binder (b) is selected from the group consisting of styrene resin, novolac resin, polyester resin, cellulose resin, polyvinyl alcohol resin, epoxy resin, melamine resin and polyvinyl butyral resin The composition for forming an electrode, characterized in that it further comprises one or more.
The method of claim 1, wherein the composition further comprises at least one additive selected from the group consisting of plasticizers, dispersants, viscosity stabilizers, antifoaming agents, pigments, UV stabilizers, antioxidants, thermal polymerization inhibitors and coupling agents. A composition for forming an electrode.
9. A plasma display panel comprising an electrode formed from the composition of any one of claims 1 and 3.

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