KR100776133B1 - Electrode composition for offset print, method for preparing a electrode by the same - Google Patents

Abstract

An electrode composition for off-set printing is provided to allow formation of a micropattern, thereby permitting fabrication of a plasma display panel with high cost efficiency by decreasing the use of silver. An electrode composition for off-set printing comprises a conductive material, an organic binder, glass frit and a solvent, wherein the organic binder includes a polymer having a glass transition temperature of -40 to -5 deg.C and a polyvinyl pyrrolidone-vinyl acetate copolymer. Particularly, the electrode composition comprises: 50-80 wt% of a conductive material; 1-20 wt% of a polymer having a glass transition temperature of -40 to -5 deg.C; 1-15 wt% of a polyvinyl pyrrolidone-vinyl acetate copolymer; and 2-15 wt% of glass frit.

Description

Electrode composition for offset printing and method for preparing electrode thereby {Electrode Composition for Offset Print, Method for Preparing a Electrode by the Same}

The present invention relates to an electrode composition for offset printing and a method for producing the electrode. More specifically, the polymer and polyvinyl pyrrolidone vinyl acetate compound having a glass transition temperature of -40 ° C to -5 ° C as an organic binder (PVP- It relates to an electrode composition for offset printing comprising VA).

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

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 used. It is known.

In the conventional method of forming the electrode, the photosensitive electrode forming paste is conventionally printed on the glass substrate through screen printing, and only the necessary portions are exposed, developed and baked using photolithography to form the electrode.

However, the photolithography method is manufactured through printing, drying, exposure, development, plasticity fixing, and the disadvantage that the manufacturing cost increases due to the loss of expensive materials by removing all the unnecessary parts through the developing process. 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 method and the like have been proposed, but there are limitations of the technology at present due to problems such as high material cost, 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, there is a disadvantage that the fine pattern is difficult and precise in thickness when forming the electrode through inkjet printing.

As another example, the film transfer method is proposed to overcome the limitations of the screen mask's precision limit and long processing time. A photosensitive electrode composition is formed on a film, transferred onto a substrate, and then exposed and developed to form an electrode pattern on the substrate. The method of forming still has the disadvantage of showing a limitation in reducing the loss of expensive materials.

In order to solve the above disadvantages, the present invention reduces the number of processes compared to the existing process by printing, drying, and firing the process number through offset printing, and prints only the necessary parts, thereby reproducing a fine electrode pattern without reproducibility on the substrate. A composition that can be formed has been developed.

The present invention has been made to solve the above problems, an object of the present invention is to provide a low cost, high efficiency plasma display panel and a method of manufacturing the same by developing a composition that enables the formation of fine patterns through offset printing will be.

One aspect of the present invention for achieving the above object is an electrode composition for offset printing comprising a conductive material, an organic binder, a glass frit and a solvent, wherein the glass transition temperature as the organic binder is -40 ℃ to -5 ℃ An electrode composition for offset printing comprising a polymer and a polyvinyl pyrrolidone vinyl acetate compound.

Another aspect of the present invention for achieving the above object is

a) preparing a composition of the present invention;

b) filling the gravure roll intaglio groove with the composition prepared in step a);

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

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

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

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

Since 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 the electrode by heat treatment such as post-printing, first, the offset printing is described first. do.

The offset printing in the present invention is divided into two processes, an off process and a set process. First, the present invention is formed on 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 the off process. After filling the composition by using a metal blade to perform a doctoring (Doctoring) step of scraping the composition overflowed on the gravure roll, after the off step is a continuous squeezing of the blanket roll and the gravure roll filled with the composition It rotates while transferring the composition filled in the gravure roll intaglio groove to the blanket roll surface which becomes 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.

In the offset process, the paste in the intaglio grooves on the gravure roll is transferred to the silicon blanket in a continuous manner without pattern projections and disconnection of the wiring. The offset for transferring the composition transferred onto the silicon blanket onto the glass substrate again with a fine electrode pattern without residues. It is an object of the present invention to provide an electrode composition for printing.

Offset printing electrode composition of the present invention for achieving the above object

a) 50 to 80% by weight of conductive material;

b) 1 to 20% by weight of a polymer having a glass transition temperature of -40 ° C to -5 ° C;

c) 1 to 15 weight percent of polyvinyl pyrrolidone vinyl acetate copolymer;

d) 2-15 wt% glass frit;

And a solvent as the residual amount.

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

The content of the conductive material is preferably 50% by weight 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 80% by weight, the transfer may be performed in performing offset printing. It may not be normal, and the thickness of the electrode may be too thick.

In the organic binder used in the present invention, it is preferable to use a polymer having a glass transition temperature of −40 ° C. to −5 ° C. together with a polyvinyl pyrrolidone vinyl acetate copolymer.

The polymer having a glass transition temperature of −40 ° C. to −5 ° C. may be an acrylic resin, a water-soluble cellulose resin, a polyvinyl alcohol resin, an epoxy resin, or a melamine, which is a copolymer of an ethylenically unsaturated monomer and another ethylenically unsaturated monomer copolymerizable therewith. Resin, polyvinyl butyral resin, etc. can be mentioned, These can be used individually or in mixture of 2 or more types. The content of the polymer is preferably 1 to 20% by weight of the total composition, more preferably 5 to 15% 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 20% by weight, many pores are generated on the electrode surface after firing. There may be a problem that the conductivity is lowered.

In addition, the polymer having a glass transition temperature of −40 ° C. to −5 ° C. preferably has a structure represented by Formula 1, a weight average molecular weight of 1,000 to 200,000, and an acid value of 20 to 250 mgKOH / g.

In addition, the polyvinylpyrrolidone vinyl acetate compound stabilizes the dispersion of the metal paste, reduces fluidity, transfers to the blanket without disturbing the pattern during the off process, and improves the film strength of the pattern on the blanket in the set process. It can have the advantage of transferring the pattern seamlessly. In addition, it has the advantage of increasing the number of continuous prints by minimizing the swelling of the solvent on the blanket by the strong solvent absorption.

The content of the polyvinyl pyrrolidone vinyl acetate copolymer is preferably 1 to 15% by weight of the total composition. When the content of the copolymer is less than 1% by weight, continuous printing may be degraded within 50 sheets of continuous printing, and in the case of 15% by weight, the viscosity may be increased to decrease off characteristics.

In the present invention, as the solvent to dissolve the organic binder 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. When using a solvent with a boiling point lower than 100 ° C, the paste dries easily during the doctoring process, resulting in defects in the pattern when transferring to the blanket.When using a solvent above 300 ° C, the paste transferred to the blanket is too slow to dry. There is a problem that a residue remains on the blanket when transferring to the 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, Texanol, alpha terpineol, kerosene, mineral spirits and dihydroterpineol, diethylene glycol butyl ether, diethylene glycol ethyl ether, dipropylene methyl ether, dihexylene glycol ethyl ether The above can be used, but is not necessarily limited thereto.

In addition, in this invention, 2 or more types of organic solvent whose boiling point is 100-150 degreeC, and whose boiling point are 200-300 degreeC can be mixed and used. When two or more types of organic solvents are mixed, the mixing ratio thereof is preferably 1/9 to 9/1. If the mixing ratio is less than 1/9, there is a problem that the transfer on the paste substrate during the set process is not good, and if it exceeds 9/1, the paste may be dried quickly in the gravure roll yarn in the doctoring process, and thus may not be turned off normally. have.

In addition, in the present invention, the glass frit has a function of increasing the adhesion between the conductive material and the substrate, and has a softening point of 300 to 600 ° C., mainly composed of lead oxide, bismuth oxide, zinc oxide, and the like. It is preferable that it 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 the glass frit is preferably 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 baking is not easy. If it is more than 20% by weight, the content of the conductive material or the organic binder is relatively low, and the conductivity and mechanical strength of the electrode pattern may be lowered.

The composition of the present invention may further include a plasticizer in order to adjust the solubility of the organic binder in the solvent 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 characteristics. 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, epoxy, 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.

Another aspect of the present invention relates to the electrode forming method described above. When manufacturing a transparent electrode by the method of this invention,

a) preparing a composition of the present invention;

b) filling the gravure roll intaglio groove with the composition;

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

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

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

It includes.

Hereinafter, the present invention will be described in more detail with reference to examples, but these are only for the purpose of explanation and should not be construed as limiting the protection scope of the present invention.

Example  One.

4.5% by weight of a texanol solution containing 40% by weight of methacrylic acid / 2-ethylhexyl methacrylate / butyl acrylate copolymer (PB21, KCC), a solution of PVP-VA copolymer having a solid content of 60% (S630, ISP ) 14%, mixed with 0.2% by weight of malonic acid (Aldrich), 65% by weight of silver powder, 5.8% by weight of glass frit (Phoenix PDE, PD130) as a viscosity stabilizer, and then stirred with a ceramic 3 roll mill After kneading and dispersing, dipropylene glycol methyl ether was added thereto as a solvent to 10.5% by weight to adjust the viscosity to obtain a composition.

Example  2.

Example except that 8.5% by weight of texanol solution containing 40% by weight of methacrylic acid / 2-ethylhexyl methacrylate / butyl acrylate copolymer and 10% by weight of PVP-VA copolymer solution (manufactured by S630 ISP) The same procedure was followed.

Example  3.

Example 1 except that 14% by weight of texanol solution containing 40% by weight of methacrylic acid / 2-ethylhexyl methacrylate / butylacrylate copolymer and 4.5% of PVP-VA copolymer solution (manufactured by S630 ISP) were used. The same procedure was followed.

Comparative example  One.

The same procedure as in Example 1 was carried out except that only 18.5% of PVP-VA copolymer solution (manufactured by S630 ISP) was used alone.

Comparative example  2.

The same procedure as in Example 1 was conducted except that 18.5 wt% of a texanol solution containing 40 wt% of methacrylic acid / 2-ethylhexyl methacrylate / butylacrylate copolymer was used alone.

The 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 protrusion, no wiring

Good: Slight pattern breaks or breaks in wiring

Poor: Pattern part protrusion, disconnection of wiring occurs a lot

2. Set Process

Very good: No pattern protrusion, no wiring

Good: Slight pattern breaks or breaks in wiring

Poor: Pattern part protrusion, disconnection of wiring occurs 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)

Excellent: The difference between the maximum and minimum line widths is 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

5. Continuous printability

Excellent: Line width change within 5 microns after 200 consecutive prints

Good: Line width change within 10 microns after 200 consecutive prints

Poor: Line width change over 20 microns after 200 consecutive prints

Referring to Table 1, it can be seen that Examples 1 to 3 show good results in all evaluation items. Comparative Example 1 in the continuous printing Comparative Example 2 showed a poor in the continuous printing and the straightness of the electrode.

Although preferred embodiments have been described above, various modifications and variations can be made without departing from the spirit and scope of the invention, so the appended claims include such modifications and variations that fall within the spirit of the invention.

In the plasma display panel and the method of manufacturing the same according to the present invention as described above, the front panel and the back panel of the plasma display panel in which the electrode is formed by using the electrode composition for offset printing of the present invention are fast enough to reproduce sufficient fineness and fine patterns. It can be produced at a speed. In addition, it is possible to manufacture a lower cost plasma display panel by reducing the cost of materials by reducing the use of expensive conductive silver powder by forming only necessary portions of the electrode.

Claims (6)

An electrode composition for offset printing comprising a conductive material, an organic binder, a glass frit, and a solvent, wherein the organic binder comprises a polymer having a glass transition temperature of -40 ° C to -5 ° C and a polyvinyl pyrrolidone vinyl acetate copolymer. Electrode composition for offset printing, characterized in that. The method of claim 1, a) 50 to 80% by weight of conductive material; b) 1 to 20% by weight of a polymer having a glass transition temperature of -40 ° C to -5 ° C; c) 1 to 15 weight percent of polyvinyl pyrrolidone vinyl acetate copolymer; d) 2-15 wt% glass frit; And a solvent as a residual amount. The composition for forming an electrode for offset printing according to claim 1, wherein the glass transition temperature is -40 ° C to -5 ° C. [Formula 1]

The composition for forming an electrode for offset printing according to claim 1, wherein the solvent is a mixture of a solvent having a boiling point of 100 to 150 ° C and a solvent having a boiling point of 200 to 300 ° C. The monomer, oligomer and trimer of claim 1, wherein the composition is a plasticizer, phthalic acid ester, adipic acid ester, phosphate ester, trimellitic acid ester, citric acid ester, epoxy, polyester, glycerol and a water-soluble, high boiling point acrylic compound monomer. The composition for forming an electrode for offset printing, further comprising at least one selected from the group consisting of: a) preparing the composition of any one of claims 1 to 5; b) filling the gravure roll intaglio groove with the composition prepared in step a); c) transferring the composition filled in the gravure roll onto a blanket roll of silicone rubber; d) transferring the composition transferred onto the blanket roll to a glass substrate; And e) drying and firing the composition transferred to the glass substrate.