KR20090048314A - Electrode forming composition comprising aluminum powder and silver powder and an electrode manufactured using the same - Google Patents

Abstract

Firing is possible even at a temperature of 600 ° C. or less, and there is provided a composition for forming an electrode, which hardly increases the resistance even after the firing and refiring process. The electrode-forming composition of the present invention is 30 to 95% by weight of the conductive filler mixed with aluminum (Al) powder of 1 ~ 20㎛ diameter and silver (Ag) powder of 0.01 ~ 20㎛ diameter; 3 to 60 weight percent organic binder; And a solvent as the residual amount. There is also provided an electrode and a plasma display panel produced using the composition.

600 ° C, resistance value, composition, electrode, silver powder, aluminum powder

Description

Electrode composition comprising an aluminum powder and silver powder and an electrode manufactured by using the same. {COMPOSITION FOR FABRICATING THE ELECTRODE COMPRISING SILVER POWDER AND ALUMINIUM POWDER AND ELECTRODE MADE BY THE SAME}

The present invention relates to a composition for forming an electrode and an electrode manufactured using the same, and more particularly, a composition for forming a bus electrode or an address electrode of a plasma display panel which can be baked at a temperature of 600 ° C. or less without a large change in resistance value, and It relates to an electrode manufactured using this.

Devices such as resistor elements, ceramic capacitors, thermistors, varistors, plasma display panels (PDPs) and the like are silver fillers (silver-)

The electrode was formed by firing after patterning by using a composition containing a pattern, such as screen printing, offset printing, photolithography.

As such, when only silver powder is used as the conductive filler in the composition for forming an electrode, manufacturing cost increases.

In order to solve this problem, research has been conducted to find a conductive filler material which is relatively inexpensive and can replace silver powder.

One of them is to use an aluminum component as a conductive filler instead of silver powder. When aluminum is subjected to a firing process in air, it has a drawback that the electrical conductivity of the electrode which is oxidized and finally manufactured is drastically reduced.

In addition, in consideration of the fact that the composition undergoes a repeated firing process when forming an electrode using a composition, when aluminum is used as the conductive filler, the oxidation degree of aluminum increases with each firing process, so that the conductivity decreases rapidly. there was.

Therefore, much research is needed to develop a composition for forming an electrode in which a conductive filler is used which is relatively inexpensive and does not have a large change in resistance even after repeated firing processes, replacing silver powder having a high price and migration problems. .

The problem to be solved by the present invention is to provide a composition for forming an electrode that can be fired at a temperature of 600 ℃ or less, there is almost no increase in the resistance value even after repeated firing in air.

Another object of the present invention is to provide an electrode and a plasma display panel using the composition.

The objects to be achieved by the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The composition for forming an electrode according to the present invention for solving the above problems is 30 to 95% by weight of a conductive filler mixed with aluminum (Al) powder of 1 ~ 20㎛ diameter and silver (Ag) powder of 0.01 ~ 20㎛ diameter; 3 to 60 weight percent organic binder; And a solvent as the residual amount.

The electrode of the present invention for solving the other problem is patterned to the desired electrode shape using the DFR method, screen printing method, offset printing method, photolithography method, and the firing process at a temperature of 450 ~ 600 ℃ It is characterized by being formed.

According to the composition for forming an electrode according to the present invention can be used in the manufacture of a plasma display panel by firing at a temperature of 600 ℃ or less, even after repeated firing, the change in the resistance value of the electrode is finally formed Almost no.

In addition, there is an advantage that the manufacturing cost can be lowered than manufacturing the electrode using only silver powder.

An electrode forming composition according to an embodiment of the present invention includes a conductive filler, glass frit, an organic binder, and a solvent.

As the conductive filler, a mixture of aluminum powder and silver powder is used.

When the conductive filler is composed of the above components, the manufacturing cost can be significantly lowered compared to using only silver powder, and at the same time, even if the electrode is formed through a recalcination process after firing at a temperature of 600 ° C. or lower, It has been found through the present invention that there is no major change.

The aluminum powder used as the first component of the conductive filler has a diameter of 1 to 20 μm, and the reason is that when using less than 1 μm, the final electrode is difficult to obtain desired electrical conductivity. This is because it is difficult to obtain a desired electrode pattern when using more than 20 µm.

The aluminum powder used in the present invention may mean a pure aluminum powder, but substantially one or more elements selected from silver, copper, silicon, tin, chromium, germanium, and the like in an independent form or alloy of the aluminum powder. It may be included in the form of).

The silver powder used as the second component of the conductive filler is one having a diameter of 0.01 to 20 µm, more preferably 0.05 to 15 µm. When the silver powder has a diameter of less than 0.01 μm, the resistance value at the initial stage of firing is high, and when it exceeds 20 μm, the roughness of the surface of the electrode to be finally formed is increased, and thus the desired shape is obtained. This is because pattern formation becomes difficult.

In this case, the silver powder may include not only pure silver powder but also a trace amount of impurities.

The ratio of the conductive filler in the total composition of the present invention has a value of 30 to 95% by weight based on the weight%, the reason that should have such a content ratio is less than 30% by weight is prepared using the composition This is because the electrode is difficult to obtain a desired degree of conductivity, and when it exceeds 95 wt%, adhesion to the substrate and printability may not be good.

 (The weight unit used in the present invention is used to indicate the content ratio based on weight among the components, and may use the term "parts by weight" instead of weight percent throughout the specification.)

The mixing ratio of the silver powder and the aluminum powder included as the component of the conductive filler is the ratio of the conductive filler in the total composition, that is, the mixing ratio of the silver powder: aluminum powder is 1 to 20% by weight: It is preferable to use 29 to 75% by weight because the increase in resistance increases after repeated firing when the content of silver powder is less than 1% by weight, and when the content of the electrode pattern that is finally formed exceeds 20% by weight. This is because a silver phenomenon may cause migration due to the movement of electrons, and the effect of falling manufacturing prices is also minimal.

The organic binder is added in order to mix the conductive filler and the glass frit in the composition of the present invention and to prepare a composition having a predetermined viscosity, thereby enabling the production of an electrode pattern for the firing process.

Examples of the organic binder used in the present invention include carboxyl group-containing monomers such as acrylic acid, methacrylic acid and itaconic acid, and ethylenically unsaturated doubles such as acrylic esters (methyl acrylate, ethyl methacrylate, etc.), styrene, acrylamide, and acrylonitrile. At least one selected from copolymers obtained by copolymerizing with monomers having a bond may be selected and used.

The content of the organic binder is 3 to 60% by weight, preferably 5 to 50% by weight. When the content of the organic binder is less than 3% by weight, the viscosity may be too low after the paste is prepared or the adhesion may be reduced after printing and drying. When the content of the organic binder exceeds 60% by weight, the organic binder is excessively present to decompose the organic binder during firing. Is not made smoothly may cause a disadvantage that the resistance is increased.

The composition of the present invention includes a solvent (solvent) as the residual amount, the solvent to dissolve the organic binder and to adjust the viscosity of the composition to be prepared to enable the production of a paste easy to apply.

The solvent used in the present invention has a boiling point of 120 ° C. or more commonly used in the electrode forming composition, methyl cellosolve, ethyl cellosolve, butyl cellosolve, aliphatic Alcohol, α-terpineol, β-terpineol, dihydro terpineol, Dihydro-terpineol, ethylene glycol, ethylene glycol mono butyl ether , Butyl Cellosolve Acetate (Butyl Cellosolve acetate), Texanol (Texanol), mineral spirits (Mineral spirit), organic acids, oleic acid (oleic acid) and the like, these may be used alone or in combination of two or more.

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 added. Preferably it is used in the range of 1-68 weight%.

In addition, the present invention may further include 1 to 30 parts by weight of glass frit with respect to 100 parts by weight of the total composition as an inorganic binder to improve adhesion to the substrate.

The glass frit is characterized in that the metal oxide glass containing at least one component of PbO, Bi ₂ O ₃ , SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , ZnO, Al ₂ O ₃ components, glass transition It is preferable that temperature Tg has 300-600 degreeC.

The reason why the glass frit has the above glass transition temperature value is that if the softening point is lower than 300 ° C., the shrinkage becomes too large. Therefore, the electrode has a large edge. There is a problem that the resistance rises.

In addition, if the addition amount of the glass frit is less than 1% by weight, it is difficult to realize the effect expected in the present invention, when it exceeds 30% by weight, the amount of the conductive filler is relatively reduced to form a desired level of conductivity in the electrode formed It can be difficult to get.

In addition, in the present invention, at least one additive selected from UV stabilizers, viscosity stabilizers, antifoaming agents, dispersing agents, leveling agents, antioxidants, thermal polymerization inhibitors, etc. may be added as necessary to improve the flow characteristics, process characteristics, and stability of the electrode composition. It may be further included, these are all known enough to be commercially available to those of ordinary skill in the art, so specific examples and description thereof will be omitted.

The composition for forming an electrode described above may produce an electrode using at least one of a dry film resistor (DFR) method, a screen printing method, an offset printing method, a coater method, and a photolithography method.

In particular, when the photolithography method is used in preparing the electrode, the present invention further includes a photopolymerizable compound and a photoinitiator in the composition.

In the present invention, the photopolymerizable compound is a polyfunctional monomer or oligomer used in the photosensitive resin composition, for example, ethylene glycol diacrylate, triethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6 -Hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacryl Latex, dipentaerythritol hexaacrylate, bis phenol A diacrylate, trimethylolpropane triacrylate, noblock epoxy acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacryl Propylene glycol dimethacrylate, 1,4-butanediol dimethacryl One or more selected from the group consisting of a rate and 1,6-hexanediol dimethacrylate can be used.

The content of the photopolymerizable compound is preferably 1 to 20 parts by weight based on 100 parts by weight of the electrode forming composition. If the content is less than 1 part by weight, the photocuring may not be performed completely, which may cause a problem of pattern dropout during development. If the content is more than 20 parts by weight, the amount of the polyfunctional monomer or oligomer may be large, causing problems of decomposition of organic materials. There may be a problem with the resistance rise.

In addition, the photopolymerization initiator in the present invention can be used as long as it can exhibit an excellent photoreaction in the ultraviolet wavelength range of 200 to 400nm, generally one selected from the group consisting of benzophenone-based, acetophenone-based, triazine-based compounds The above can be used.

The amount of the photopolymerization initiator added is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the electrode forming composition.

After patterning at a desired location through the above process, the process is primarily a room temperature drying process, and after the baking process at a temperature of 100 ~ 200 ℃ to form an electrode pattern having a certain strength.

Then, when the firing (firing) at a temperature of 450 ~ 600 ℃ All organic binder and the solvent inside the patterned composition film is detached, the glass binder, the inorganic binder is melted to bind the conductive filler.

The firing step is not carried out once, but may be repeated two or three times according to a process such as a dielectric.

1 is an exploded perspective view showing a plasma display panel manufactured using a 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 for storing charge generated in the panel 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 a composition according to an embodiment of the present invention. Specifically, one of a screen printing method, an offset printing method, and a photolithography method is used. Is formed by.

Typically, a method of forming an electrode by photolithography is performed by the following steps.

(a) applying the composition of the present invention to a glass substrate with a thickness of 5 ~ 40㎛;

(b) drying the applied composition at a temperature of 80-150 ° C. for about 20-60 minutes;

(c) performing an ultraviolet exposure process using a photomask on the dried composition film;

(d) removing the exposed or unexposed areas of the composition film through a developing process;

(e) drying and baking the remaining composition film at a temperature of 500 to 600 ° C

Hereinafter, when the electrode is formed using the composition for forming an electrode according to the present invention, it is possible to bake at a temperature of 600 ° C. or lower, and even after repeated firing, there is almost no change in the line resistance value, so that the final conductivity is formed. This experiment is described with specific experimental examples. Details that are not described here are omitted because they can be sufficiently inferred by those skilled in the art.

1. Preparation of Electrode Formation Composition

<Example 1>

49.59% by weight of Al powder (high purity chemical research center, aluminum atomized powder, average particle diameter 5㎛) as conductive filler, 9.15% by weight of Ag powder (Dowa, 3-11F, average particle diameter 1.5㎛), glass frit, containing no lead and softening point 9.83 weight% of LF6002 LF6002 with an average particle diameter of 480 DEG C and an average particle diameter of 18.83 weight% of an acrylic copolymer (named SPN # 30-1) as an organic binder, and 12.61 weight of Texanol as a solvent. After mixing and stirring using%, a composition kneaded and dispersed with a ceramic 3-roll mill was obtained.

<Example 2>

A composition was prepared in the same manner as in Experiment 1, except that 3.05% by weight of Ag powder was used in 55.69% by weight of Al powder as the conductive filler.

<Example 3>

A composition was prepared in the same manner as in Experiment 1, except that 1.02% by weight of Ag powder was used in 57.72% by weight of Al powder as the conductive filler.

<Example 4>

A composition was prepared in the same manner as in Experiment 1, except that 9.7 wt% of Ag founder (Tokusen nano, particle size 300nm) was used in 49.04 wt% of Al powder as the conductive filler.

<Example 5>

A composition was prepared in the same manner as in Experiment 1, except that Ag 23 wt% (Tokusen nano, particle size 300 nanometer) was used in 55.51 wt% of Al powder as the conductive filler.

<Example 6>

49.59% by weight of Al powder (high purity chemical research center, aluminum atomized powder, average particle diameter 5㎛) as conductive filler, 9.15% by weight of Ag powder (Dowa, 3-11F, average particle diameter 1.5㎛), glass frit, containing no lead and softening point 7.83% by weight of Participant's LF6002 with an average particle diameter of 480 DEG C and an average particle diameter of 1.5 µm, 18.83% by weight of an acrylic copolymer (named SPN # 30-1) as an organic binder, 1.5% by weight of a photoinitiator (Shiba, IC369), A photopolymerizable compound (Sartomer, SR494) was mixed with 7 wt% and 6.1 wt% of Texanol (Eastman Chemical Co., Ltd.) as a solvent, followed by stirring and kneading and dispersing with a ceramic 3-roll mill.

Comparative Example 1

A composition was prepared in the same manner as in Experiment 1, except that 58.74 wt% of spherical aluminum powder (high purity chemical laboratory, aluminum atomized powder) having an average particle diameter of 5 μm was used as the conductive filler.

Comparative Example 2

Experiment was conducted except that 58.24 wt% of spherical aluminum powder (high purity chemical research institute, aluminum atomized powder) and 0.5 wt% Ag powder (Dowa, 3-11F, average particle diameter 1.5㎛) were used as the conductive filler. The composition was prepared in the same manner as in Example 1.

2. Formation of Thick Film Electrode Using Compositions

The compositions prepared according to Examples 1 to 5 and Comparative Examples 1 to 2 were applied to a 10 cm ㅧ 10 cm high melting point glass plate using a PI1210 coater manufactured by Tester Sangyo Co., Ltd., followed by drying at room temperature and baking at 110 ° C. After coarse, after firing in a belt furnace at 560 ° C., a peak of 15 minutes, and an hour and a half after inout, a pattern of 25 μm was formed, and the resistance value was measured. The results are shown in Table 1 below.

In addition, the composition of Example 6

(a) applying the composition to the substrate to a thickness of 25 μm;

(b) drying the applied composition at a temperature of 110 ° C. for about 20 minutes;

(c) performing an ultraviolet exposure process using a photomask on the dried composition film;

(d) removing the exposed or unexposed regions of the composition film through a developing process;

(e) calcining the remaining composition film at a temperature of 560 ° C.

An electrode was manufactured through the above, and the resistance value of the prepared electrode was measured, and the results are shown in Table 1.

3. Measurement of resistance value change rate according to refiring of electrode

After measuring the initial resistance value of the electrode pattern prepared by using the compositions of the Examples and Comparative Examples, and then repeated two times firing was measured to change the resistance value, the results are shown in Table 1.

Referring to Table 1, in the examples using the size and content of the Al powder and Ag powder in the range of the present invention, it can be seen that the initial resistance value after the primary firing is more than two times lower than the comparative examples, It can be seen that even though the second and third firing processes, the increase rate of the resistance is insignificant or the resistance is decreasing.

When comparing the data of Example 1, Example 4, Example 2 and Example 5, even if the Ag powder having a particle size of any size is used within the particle size range of the Ag powder proposed in the present invention, the initial resistance value and the repeated firing It can be seen that the trend of change in resistance is similar.

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

Claims (12)

30 to 95 wt% of a conductive filler in which aluminum (Al) powder having a diameter of 1 to 20 µm and silver (Ag) powder having a diameter of 0.01 to 20 µm are mixed; 3 to 60 weight percent organic binder; And The composition for electrode formation containing a solvent as a residual amount. The method of claim 1, The silver (Ag) powder: the mixing ratio of the aluminum powder is 1 to 20% by weight: the composition for forming an electrode, characterized in that 29 to 75% by weight. The method of claim 1, The aluminum powder is an alloy for forming an electrode, characterized in that the alloy of the aluminum component and at least one element selected from silver, copper, silicon, tin, chromium, germanium and the like. The method of claim 1, The organic binder includes monomers having carboxyl group-containing monomers such as acrylic acid, methacrylic acid and itaconic acid and ethylenically unsaturated double bonds such as acrylic esters (methyl acrylate, ethyl methacrylate, etc.), styrene, acrylamide, and acrylonitrile; It is 1 or more types chosen from the copolymer obtained by copolymerization, The composition for electrode formation characterized by the above-mentioned. The method of claim 1, The solvent is methyl cellosolve (Methyl Cellosolve), ethyl cellosolve (Ethyl Cellosolve), butyl cellosolve (Butyl Cellosolve), aliphatic alcohol (Alcohol), α-terpineol, β-terpineol, dihydro Dihydro-terpineol, Ethylene Grycol, Ethylene glycol mono butyl ether, Butyl Cellosolve Acetate, Texanol, Mineral Spirit spirit), an organic acid, oleic acid (oleic acid) composition for forming an electrode, characterized in that at least one selected from. The method of claim 1, The composition for forming an electrode, characterized in that it further comprises 1 to 30 parts by weight of glass frit (glass frit) with respect to 100 parts by weight of the total composition. The method of claim 6, The glass frit is a metal oxide-based glass comprising at least one component of PbO, Bi ₂ O ₃ , SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , ZnO, Al ₂ O ₃ components Composition. The method of claim 6, The glass transition temperature (Tg) of the glass frit is an electrode forming composition, characterized in that 300 ~ 600 ℃. The method of claim 1, The composition is an electrode forming composition, characterized in that it further comprises 0.01 to 10 parts by weight of the photopolymerization initiator with respect to 100 parts by weight of the composition. The method of claim 1, The composition of claim 1, wherein the composition further comprises at least one additive selected from antifoaming agent, leveling agent, UV stabilizer, antioxidant, and thermal polymerization inhibitor. An electrode formed by patterning the composition of claim 1 to a desired electrode shape using a DFR method, a coater method, a screen printing method, an offset printing method, a photolithography method, and a baking process at a temperature of 450 to 600 ℃ . A front substrate and a rear substrate facing the front substrate; A transparent electrode in which the front substrate and the rear substrate are arranged in the transverse direction on the front substrate on the surface facing each other; A bus electrode formed on the transparent electrode; In the plasma display panel comprising an address electrode formed in the longitudinal direction on the rear substrate of the surface facing the front substrate and the rear substrate, And the bus electrode and / or the address electrode are the electrodes of claim 11.

Images