KR20090065092A - Electrode composition for offset printing, method for preparing a electrode and a plasma display panel using the same - Google Patents

Abstract

An electrode composition for the offset printing, and a method for forming an electrode for the offset printing by using the composition are provided to improve the formation velocity of pattern and reproducibility by preventing the error such as branch or dumbbell on the transferred pattern. An electrode composition for the offset printing comprises 50-90 wt% of a conductive material, 1-30 wt% of an organic binder, 1-20 wt% of a glass frit, 1-10 wt% of an anionic dispersant, and the balance of an organic solvent. An electrode for the offset printing is formed by filling the electrode composition into a gravure roll intaglio groove; transferring the filled composition on the blanket roll made of silicone rubber; transferring the composition transferred on the blanket roll on a glass substrate; and drying and sintering the composition transferred on the glass substrate.

Description

Electrode composition for offset printing, electrode formation method and plasma display panel using the same {Electrode Composition for Offset Printing, Method for Preparing a Electrode and a Plasma Display Panel using the Same}

The present invention relates to an electrode composition for offset printing, a method of forming an electrode using the same, and a plasma display panel.

Plasma display panel (PDP) is one of flat panel displays, and is a type of display which is rapidly expanding in recent years while competing with LCD and projection TV.

Taking an AC (AC) -type PDP as an example, the structure is a back surface having a cell substrate composed of a transparent substrate (maintenance electrode) and a glass substrate called a front plate in which a bus electrode is covered with a dielectric layer, and an address electrode, a dielectric layer, a partition wall, and a phosphor. It is comprised including the glass substrate called plate, and arrange | positioned so that the electrodes of both surfaces may orthogonally cross.

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 inside the partition cell by the ultraviolet rays generated at this time. 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 plate is formed. Therefore, in order to improve the quality (contrast) of the displayed image, a method of forming a black electrode between the transparent electrode and the bus electrode as a method of suppressing the recognition from the back of the bus electrode of the front plate corresponding to the display surface is also required. It is known.

A conventional method of forming the electrode is a method of forming the electrode by performing a front-side printing of the photosensitive electrode forming paste on the glass substrate through screen printing and exposing, developing and firing only the necessary portions using the photolithography method. .

However, the photolithography method removes unnecessary parts through the development process after printing all the unnecessary parts, resulting in the loss of expensive materials and increasing manufacturing costs, and many processes because they are manufactured through printing, drying, exposure, developing, and firing processes. It has the disadvantage of taking time.

In addition, the metal and polyester screen masks used for screen printing have a disadvantage in that the printed film thickness is changed due to elongation and deformation as the use time elapses.

In order to solve the above problems, inkjet printing, film transfer methods and the like have been proposed, but there are problems such as high material costs, a large number of processes, and expensive equipment.

For example, in the case of inkjet printing, in order to prepare ink for inkjet printing, an expensive conductive powder having a nano size is required, and the manufacturing process thereof is complicated, and the manufacturing cost is high. In addition, when forming the electrode through inkjet printing it is difficult to have a fine pattern of precision, the thickness is not enough.

Another example of the film transfer method is proposed to overcome the disadvantages of the precision limitation of the screen mask and the long processing time. The photosensitive electrode composition is formed on a film, transferred onto a substrate, and then exposed and developed to form an electrode on the substrate. The method of forming patterns still presents a limit to reducing the loss of expensive materials.

The offset printing method, which has been used to compensate for the above disadvantages, simplifies the number of processes to the process of printing, drying and firing, dramatically reducing the existing process and printing only necessary parts, thereby reproducing fine electrode patterns without loss of expensive materials. Can be formed on.

The offset printing process is composed of an off process and a set process. In the off process, it is required to secure the straightness of the pattern without a dumbbell or a branch defect in the printing pattern. In addition, in the set process, the turned off electrode must be stably transferred to the substrate.

When the electrode composition is manufactured to have a good flowability but a pattern without dumbbells, a piling defect, in which a transfer residue remains on a blanket during a subsequent set process, appears, and, conversely, a transfer residue suitable for the set process. When manufacturing an electrode composition with high viscosity so that this may not remain, there exists a problem that the defects, such as a branch and a dumbbell, arise in the printing pattern of an off process.

Accordingly, there is a need for an offset printing electrode composition capable of simultaneously satisfying the requirements of such an off process and a set process.

The present invention has been made to solve the above problems, to provide a plasma display panel comprising an electrode composition having an excellent pattern characteristics and excellent set characteristics at the same time when printing the electrode by offset printing and an electrode manufactured using the same will be.

The technical problem to be achieved by the present invention is not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object,

According to one aspect of the invention, in the offset printing electrode composition comprising a conductive material, an organic binder, a glass frit, a dispersant and an organic solvent, an offset printing electrode comprising 1 to 10% by weight of an anionic dispersant as a dispersant The composition can be presented.

In addition, according to another aspect of the present invention,

a) filling the gravure roll intaglio groove of the electrode composition of the present invention;

b) transferring the composition filled in the gravure roll onto a blanket roll of silicone rubber;

c) transferring the composition transferred onto the blanket roll to a glass substrate; And

and d) drying and firing the composition transferred to the glass substrate.

In addition, according to another aspect of the present invention, an electrode formed by the electrode forming method and a plasma display panel including the same can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The electrode composition according to the present invention is to form a fine pattern reproducibly on the front plate and the back plate of the plasma display panel by offset printing, and to form an electrode by heat treatment such as baking after printing, the offset printing will be described in detail first .

Offset printing is divided into two processes, an off process and a set process. First, the composition according to the present invention is filled onto a gravure roll having a fine pattern having a line width of 50 to 150 μm and a depth of 10 to 50 μm before performing the off process, and then scraping the composition that has overflowed on the gravure roll using a metal blade. I perform a doctoring process. Thereafter, the blanket roll and the gravure roll filled with the composition are sequentially pressed and rotated to perform an off process of transferring the composition filled in the gravure roll intaglio groove to the blanket roll surface made of the silicone rubber surface.

The set process is a process of compressing and rotating a blanket made of a silicon rubber surface and a glass substrate to transfer the composition transferred on the silicon blanket surface onto the glass substrate again.

The electrode composition for offset printing of the present invention comprises 50 to 90% by weight of the conductive material, 1 to 30% by weight of the organic binder, 1 to 20% by weight of the glass frit, 1 to 10% by weight of the anionic dispersant and the remaining amount of the organic solvent. can do.

The conductive material used in the electrode composition for offset printing of the present invention is for increasing the electrical conductivity, and is a group consisting of gold, platinum, palladium, silver, copper, aluminum, nickel or alloys thereof having a diameter ranging from 0.1 μm to 3 μm. One or more conductive powders selected from can be used, preferably having a diameter in the range from 0.3 μm to 2 μm.

The content of the conductive material is preferably 50% to 90% by weight, more preferably 60 to 80% by weight. If the content is less than 50% by weight, it may be difficult to secure sufficient conductivity of the electrode, when the content exceeds 90% by weight, the transfer is not normal in performing the offset printing, the thickness of the electrode may be too thick.

In the present invention, it is preferable that the organic binder is a polymer resin having a glass transition temperature of -40 ° C to -5 ° C. If the glass transition temperature of the organic binder is less than -40 ° C, a large number of protrusions are formed on the pattern during the off process and the set process. Also, when unnecessary foreign matter adheres to the transferred pattern on the glass substrate, it is not easy to remove dust by compressed air. There is a disadvantage. If the glass transition temperature exceeds -5 ° C, there is a problem in that the paste transferred on the blanket does not have adhesive force, so that the transfer on the glass substrate is not easy.

Examples of the organic binder include acrylic resins, water-soluble cellulose resins, polyvinyl alcohol resins, epoxy resins, melamine resins, polyvinyl butyral resins, and the like, which are copolymers of ethylenically unsaturated monomers with other ethylenically unsaturated monomers copolymerizable therewith. These can be used individually or in mixture of 2 or more types. The content of such an organic binder is preferably 1 to 30% by weight, more preferably 5 to 20% by weight. If the content is less than 1% by weight, it is not easy to transfer in the off and set process, sedimentation of inorganic materials such as silver powder can easily occur, and if it exceeds 30% by weight, many pores are generated on the electrode surface after firing. The problem that the conductivity of may fall may arise.

In the present invention, as the organic solvent can dissolve the binder resin can be used an organic solvent having a boiling point of 100 ~ 300 ℃, it is preferable to use the primary and secondary alcohols to reduce the silicone blanket swelling. If the solvent has a boiling point lower than 100 ° C, the paste dries easily during the doctoring process, causing defects in the pattern when transferring to the blanket.When using a solvent higher than 300 ° C, the paste transferred to the blanket is too slow to dry. There is a problem that the residue remains on the blanket when transferring to the glass substrate.

Examples of the organic solvent include isopropyl alcohol, 2-ethylhexyl alcohol, methoxypentanol, butoxyethanol, ethoxyethoxy ethanol, butoxyethoxy ethanol, methoxy propoxy propanol, glycerol, ethylene glycol, glycerol 1, selected from the group consisting of texanol, alpha terpineol, kerosene, mineral spirits and dihydroterpineol, diethylene glycol butyl ether, diethylene glycol ethyl ether, dipropylene methyl ether and dihexylene glycol ethyl ether More than one species may be used, but are not necessarily limited thereto.

Moreover, in this invention, 2 or more types of organic solvents whose boiling point is 100-150 degreeC, and whose boiling point are 200-300 degreeC can be mixed and used.

The anionic dispersant used in the present invention is a polymeric dispersant containing an ester group, and may include the Solsperse series of Avecia Co., Ltd. (AVECIA), and specifically include Solseperse 20000 and Solseperse 24000, but are not limited thereto. It is not.

The electrode forming composition of the present invention may contain 1 to 10% by weight of the anionic dispersant, thereby printing a high-precision pattern having excellent straightness during offset printing without piling. If the content is less than 1%, the straightness of the pattern is not sufficiently improved, and if the content is more than 10%, the viscosity is too low, resulting in poor filing during printing.

In the present invention, the glass frit serves to increase the adhesion between the conductive material and the substrate. It is a softening point of 300-600 degreeC, It is preferable that lead oxide, bismuth oxide, zinc oxide, etc. are a main component, and glass transition temperature is 200-500 degreeC. It is preferable that the particle size does not exceed 5 micrometers in consideration of the film thickness used.

The content of such glass frit may be included in 1 to 20% by weight, more preferably 3 to 15% by weight of the total composition. If the content is less than 1% by weight, the adhesion between the electrode pattern and the electrode substrate after firing is not easy, and if it exceeds 20% by weight, the content of the conductive material or the organic binder is relatively low, so that the conductivity and mechanical strength of the electrode pattern is reduced. Can be degraded.

The composition of the present invention may further include a plasticizer to adjust the solubility of the organic binder soluble in the binder solution in addition to the above-described components. Plasticizers may be used having compatibility with the organic binder, it is used for the purpose of adjusting the drying properties. Examples of the plasticizer are selected from the group consisting of phthalic acid esters, adipic acid esters, phosphate esters, trimellitic acid esters, citric acid esters, epoxies, polyesters, glycerol and water-soluble, high boiling point acrylic compounds monomers, oligomers and trimers One or more may be used, but is not necessarily limited thereto.

In addition, the present invention may further include a dispersant, a viscosity stabilizer, an antifoaming agent, a coupling agent and the like as needed in addition to the above components. These additives are known to those skilled in the art, their amount or use.

According to another aspect of the present invention,

a) filling the gravure roll intaglio groove of the composition of the present invention;

b) transferring the composition filled in the gravure roll onto a blanket roll of silicone rubber;

c) transferring the composition transferred onto the blanket roll to a glass substrate; And

d) drying and firing the composition transferred to the glass substrate to form an electrode

An electrode forming method comprising a and a plasma display panel including an electrode formed through the same may be provided.

1 is an exploded perspective view showing a plasma display panel including an electrode manufactured using an electrode composition according to an embodiment of the present invention.

As shown in FIG. 1, the plasma display panel 10 manufactured using the composition according to the exemplary embodiment of the present invention includes a front substrate 100 and a rear substrate 150.

The bus electrode 112 formed on the transparent electrode 110 and the transparent electrode 110 which are arranged in the transverse direction on the front substrate 100 on the surface of the front substrate 100 and the rear substrate 150 facing each other. The MgO layer 118 is formed on the transparent electrode 110 to protect the first dielectric layer 114 and the first dielectric layer 114 and to facilitate electron emission. It is.

The address electrode 117 is formed in the longitudinal direction on the rear substrate 150 of the surface where the front substrate 100 and the rear substrate 150 face each other, and on the rear substrate 150 on which the address electrode 117 is formed. On the second dielectric layer 115 and the second dielectric layer 115, partition walls 120 in which fluorescent materials 132 corresponding to RGB are formed are formed to define pixel regions.

An inert gas such as Ne + Ar or Ne + Xe is injected into the space between the front substrate 100 and the rear substrate 150 to generate light by discharge when a voltage above a threshold voltage is applied to the electrode.

In the above PDP structure, the bus electrode 112 and the address electrode 117 are formed using the electrode composition for offset printing according to the embodiment of the present invention.

As described above, the electrode composition of the present invention enables printing without branch or dumbbell shape defects in the transfer pattern in the offset printing process, and therefore, the electrode composition is used to When the fine electrode pattern is formed, it can be usefully used because it can improve the formation speed of the pattern and implement reproducibility.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, this is presented as a preferred example of the present invention and in no sense can be construed as limiting the present invention.

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

In manufacture of the electrode composition of this invention, the specific specification of each structural component used by the below-mentioned Example and comparative example is as follows.

(a) Conductive material: silver powder with an average particle diameter of 1.5 µm (Mitsui, SPQ08S)

(b) Organic Binder: P118 (Kosehi Japan)

(c) Glass frit: POF0518 (Phoenix PDE)

(d) Anionic Dispersant: Solsperse 24000 (Avecia)

(e) Solvent: Dipropylene glycol methyl ether

(f) Viscosity Stabilizer: Malonic Acid

Example  One

7% by weight of organic binder, 0.2% by weight of malonic acid, 78.3% by weight of silver powder, 5% by weight of glass frit, 2% by weight of anionic dispersant, 7.5% by weight of solvent, and then kneaded and dispersed with a ceramic 3 roll mill To obtain a composition.

Example  2

The same procedure as in Example 1 was conducted except that 4 wt% of anionic dispersant and 5.5 wt% of solvent were used.

Example  3

The same procedure as in Example 1 was conducted except that 5.5 wt% of an organic binder, 8 wt% of anionic dispersant, and 3 wt% of a solvent were used.

Comparative example  One

The same procedure as in Example 1 was conducted except that an anionic dispersant was used and 9.5 wt% of a solvent was used.

Comparative example  2

5.5% by weight of organic binder, 0.2% by weight of malonic acid, 78.3% by weight of silver powder, 3.5% by weight of glass frit, 11% by weight of anionic dispersant, 1.5% by weight of solvent, and then kneaded and dispersed with a ceramic 3 roll mill To obtain a composition.

evaluation

Evaluation was performed by adjusting the composition of Examples 1 to 3 and the compositions of Comparative Examples 1 and 2 on an 14 cm × 14 cm sized high melting glass plate using an offset printing machine to form an electrode pattern, and then maintaining them at 100 ° C. for 10 minutes. It was dried in a belt dryer. The post-process evaluation confirmed the state transferred to the blanket after the off process, the state transferred to the substrate after the set process, and whether the residue of the paste remained on the blanket. Thereafter, the substrate was baked at 560 ° C. for 20 minutes to confirm pattern shape and resistance. The results are shown in Table 1 below.

[Evaluation standard]

1. Off process

Very good: No pattern bumps, no wiring breaks

Good: Slight pattern breaks in the wiring and wiring

Poor: Pattern protrusions and wiring breaks occur a lot

2. Set Process

Very good: No pattern bumps, no wiring breaks

Good: Slight pattern breaks in the wiring and wiring

Poor: Pattern protrusions and wiring breaks occur a lot

3. After set the blanket residue

Very good: no residue left

Good: A small amount of residue

Poor: large amount of residue left

4. Electrode straightness after printing (evaluation line width: 80 micron line)

Very good: difference between maximum and minimum line widths within 3 microns

Good: The difference between the maximum and minimum line widths is within 6 microns

Poor: The difference between the maximum and minimum line widths is greater than 15 microns

TABLE 1

Referring to Table 1, it can be seen that Examples 1 to 3 containing an appropriate amount of anionic dispersant showed good results in all evaluation items. On the contrary, in the case of containing no anionic dispersant (Comparative Example 1), the electrode straightness was poor, and in the case of containing more than an appropriate amount (Comparative Example 2), the result was poor in the residue on the blanket after the set. It was.

As a result, by adding 1 to 10% by weight of an anionic dispersant into the highly viscous electrode forming composition, it is possible to produce an electrode forming composition having excellent patternability and set characteristics simultaneously, thereby using a high efficiency plasma display. It can be seen that the manufacture of the panel is possible.

Although the preferred embodiments have been described above by way of example, various modifications and variations are possible without departing from the spirit and scope of the invention, so the appended claims include such modifications or variations that fall within the spirit of the invention.

1 is an exploded perspective view showing a plasma display panel manufactured using the composition according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: front substrate: transparent electrode

112: bus electrode: first dielectric layer

115: second dielectric layer: address electrode

118: MgO layer: bulkhead

132: phosphor: back substrate

Claims (10)

An offset printing electrode composition comprising a conductive material, an organic binder, a glass frit, a dispersant, and an organic solvent, wherein the dispersant comprises 1 to 10% by weight of an anionic dispersant. The method according to claim 1, comprising 50 to 90% by weight of the conductive material, 1 to 30% by weight of the organic binder, 1 to 20% by weight of the glass frit, 1 to 10% by weight of the anionic dispersant and the remaining amount of the organic solvent. An electrode composition for offset printing, characterized in that. The electrode composition of claim 1, wherein the conductive material is at least one conductive powder selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, nickel, and alloys thereof. The electrode composition for offset printing according to claim 1, wherein the organic binder has a glass transition temperature of -40 ° C to -5 ° C. The electrode composition for offset printing according to claim 1, wherein the glass frit has a softening point of 300 to 600 ° C and a glass transition temperature of 200 to 500 ° C. The electrode composition of claim 1, wherein the anionic dispersant is a polymer containing an ester group. The electrode composition of claim 1, wherein the anionic dispersant is at least one selected from Solseperse 20000 and Solseperse 240000. The electrode composition for offset printing according to claim 1, wherein the composition further comprises at least one member selected from the group consisting of a plasticizer, a viscosity stabilizer, an antifoaming agent, and a coupling agent. a) filling the gravure roll intaglio groove with the composition of claim 1; b) transferring the composition filled in the gravure roll onto a blanket roll of silicone rubber; c) transferring the composition transferred onto the blanket roll to a glass substrate; And d) drying and firing the composition transferred to the glass substrate. A plasma display panel comprising an electrode formed by the method of claim 9.

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