KR20160032409A - High conductive Paste composition and producing Method thereof using high temperature heat treatment - Google Patents

Abstract

The present invention relates to a method for producing a highly conductive paste by high-temperature heat treatment. More specifically, the method includes: (A) heat-treating a nano-sized carbon-based conductive filler under vacuum at a temperature of 1,500 to 1,750°C; (B) mixing the heat-treated nano-sized carbon-based conductive filler with a binder and a solvent; (C) subjecting the composition mixed in the step (B) for ultrasonication; stirring the ultrasonicated composition by an impeller for dispersion (D); and milling the composition stirred in the step (D) in a 3-roll mill (E). According to the present invention, damage to carbon structures used as fillers is recovered by heat-treating the nano-sized carbon-based conductive filler at high temperatures in vacuum, thereby producing highly conductive paste with low resistance and high electroconductivity. In addition, according to the present invention, a highly conductive paste forming a low resistance without using a metal material or a high content of a filler can be produced by using nano-sized carbon-based conductive fillers having high crystallinity through high-temperature heat treatment.

Description

TECHNICAL FIELD [0001] The present invention relates to a high conductive paste composition and a high conductive paste composition,

The present invention relates to a method for producing a high conductivity paste through a high temperature heat treatment and a high conductivity paste prepared using the same.

Carbon isotopes such as diamond, graphite, fullerene and carbon nanotubes have been discovered as a result of studies on various forms and structures of carbon isotopes. These carbon isotopes have been found to be excellent catalysts, heat transfer, energy storage, Chemical reaction, and electromagnetic reaction, and thus it is used in various application fields.

Particularly, the excellent electrical conductivity and thermal conductivity of carbon nanotubes are applied to functional materials prepared in the form of nanocomposites through nanocomposites. They are used for energy storage materials and field emission materials including chemical and physical properties of carbon nanotubes, High-performance complexes and the like.

Here, in the case of a high-functional composite having various electrical conductivity and thermal conductivity among various kinds of high-functional composites, carbon nanotubes, carbon black, carbon fibers, etc. having electrical conductivity and thermal conductivity are dispersed in a polymer as a conductive filler, Thereby imparting electrical conduction and heat conduction characteristics to the general characteristics of the polymer.

Prior art prior art related to the production of functional polymers using such carbon isotopes is disclosed in Korean Patent Registration No. 10-1294596 entitled " Composition and method for producing surface heating element paste containing carbon nanotubes " .

In such a conventional technique, a heating element paste containing carbon nanotubes is prepared, coated on a substrate, and dried to produce a planar heating element.

However, in the related art, the resistance generated due to the continuous oxidation process over time in the coated substrate by manufacturing the heating element face including the metal material together with the carbon nanotubes changes, and the electrical conductivity and the thermal conductivity are low .

In addition, the conventional art has a problem that it is difficult to maintain constant electrical conductivity and thermal conductivity by varying the structural crystallinity depending on the degree of damage of the carbon isotope provided in the production of the paste.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a technique capable of producing a highly conductive paste improved in crystallinity of a bonding structure formed by carbon, .

In order to accomplish the above object, the present invention provides a method for manufacturing a highly conductive paste by a high-temperature heat treatment, comprising the steps of: A) annealing a nano-sized carbon-based conductive filler at a temperature of 1,500 ° C to 1,750 ° C in a vacuum; A step B of mixing the heat-treated nanocarbon-based conductive filler, a binder and a solvent; A step C for performing ultrasonic treatment on the composition mixed in the step B; Stirring the ultrasonic treated composition through a dispersing impeller; And step E in which the composition stirred in step D is milled through a 3 roll mill.

Here, the composition to be mixed in step B may include 1 to 10 parts by weight of the heat-treated nanocarbon-based conductive filler; 1 to 40 parts by weight of the binder; And 1 to 40 parts by weight of the solvent.

The nano carbon based conductive filler may be selected from the group consisting of a single wall carbon nanotube, a double wall carbon nanotube, a multi wall carbon nanotube, a graphite, Fullerene, carbon black, carbon fiber, and the like.

In addition, the binder is made of a polymer material made of a polyester system.

The solvent may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dichloroethene, toluene, N, N-dimethylformamide, N-methyl Pyrrolidone (N-methylpyrrolidone).

In the step D, the dispersion impeller is stirred at a speed of 500 RPM to 600 RPM for 30 minutes to 60 minutes to uniformly mix the composition.

According to another aspect of the present invention, there is provided a high conductive paste composition comprising 1 to 10 parts by weight of a nano-sized carbon-based conductive filler; 1 to 40 parts by weight of a binder; And 1 to 40 parts by weight of a solvent, wherein the nano-carbon-based conductive filler is heat-treated in a vacuum state at a temperature of 1500 ° C to 1750 ° C.

The nanocarbon-based conductive filler may be a single wall carbon nanotube, a double wall carbon nanotube, a multi wall carbon nanotube, a graphite, Fullerene, carbon black, carbon fiber, and the like.

In addition, the binder is made of a polymer material made of a polyester system.

The solvent may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dichloroethane, toluene, N, N-dimethylformamide, N- Methylpyrrolidone. ≪ / RTI >

According to the present invention, a nano-sized carbon-based conductive filler is heat-treated at a high temperature in a vacuum state to restore the degree of damage of the carbon structure used as a filler, thereby achieving low resistance and high electrical conductivity A high conductivity paste can be produced.

Further, according to the present invention, by using nano-sized carbon-based conductive filler having high crystallinity through high-temperature heat treatment, it is possible to use a metal material and a high- A conductive paste can be produced.

1 is a flow chart illustrating a method for producing a high conductivity paste by a high temperature heat treatment according to the present invention.
2 and 3 are graphs showing Raman spectrum results according to an embodiment of the present invention.
4 is a graph showing the results of surface resistance test according to an embodiment of the present invention.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which the technical parts already known will be omitted or compressed for the sake of brevity.

≪ Explanation of a method for producing a high conductivity paste by high temperature heat treatment >

Hereinafter, how the high conductivity paste manufacturing method according to the present invention is performed through the high temperature heat treatment will be described in detail with reference to the flowchart of FIG. 1 and the experimental results of FIG. 2 to FIG.

1. High temperature heat treatment step < S100 >

In this step, the experimenter conducts a high-temperature heat treatment in a vacuum state on a nano-sized carbon-based conductive filler to be used in the production of a high-conductivity paste. In this process, the heat treatment temperature is set to 1,500 ° C to 1,750 ° C, and the heat treatment time is set to 2 hours to 4 hours.

Here, the nano carbon based conductive filler may be a single wall carbon nanotube, a double wall carbon nanotube, a multi wall carbon nanotube, a graphite, a fullerene, (Fullerene), carbon black (Carbon Black), and carbon fiber (carbon fiber).

In addition, the high-temperature heat treatment step (S100) may be performed by performing a high-temperature heat treatment process in a vacuum state to enhance thermal stability to prevent damage to the carbon structure due to the heat treatment of the conductive filler based on nano-sized carbon, By exposure, the non-carbon based molecules contained in the nano-sized carbon-based conductive filler are removed by pyrolysis and the amorphous carbon is oxidized to reduce the amorphous carbon.

As a result, a nano-sized carbon-based conductive filler that is heat-treated in a vacuum state has improved crystallinity and orientation of the carbon structure, resulting in very low electrical resistance and very high electrical conductivity. This narrows the gap between the carbon structures and increases the charge density and the mobility of the charge.

That is, irrespective of the degree of damage of the nano-sized carbon-based conductive filler used in the composition of the conductive paste, the high-temperature heat treatment step (S100) .

FIGS. 2 and 3 are graphs showing Raman spectrum results of carbon nanotubes used as a nano-sized carbon-based conductive filler, showing the stability and purity of the chemical and physical structures of carbon nanotubes It is a standard to judge.

Here, the Raman spectrum is a widely used method for confirming the purity of the shape and size of the structure that determines the mechanical and optical properties of the carbon structure and the electron behavior. In the graphs shown in FIGS. 2 and 3, (Unit: nm), and the y-axis represents a threshold (Arbitrary unit) representing the intensity.

2, the peak formed near the 1300 nm wavelength is referred to as D-band, the peak formed near 1550 nm wavelength is referred to as G-band, the degree of D-band height indicates the damage property of the material, and G The degree of band height indicates crystallinity.

That is, the D-band is a peak due to impurities or structural defects other than structural components, and the lower the degree, the higher the purity and the smaller the degree of damage.

Table 1 shows Raman spectrum results according to one embodiment of the present invention.

division Before heat treatment Heat treatment at 1500 ℃ D-band 1.11 0.95 G-band One One D / G ratio One 0.95

Here, as shown in the result graph of FIG. 2 and Table 1, when comparing the ratio of D / G in order to confirm the crystallinity of the carbon nanotubes subjected to the high-temperature heat treatment, the high temperature heat treatment is performed through step (S100) And it is confirmed that the crystallinity is increasing.

In this regard, FIG. 3 is a graph showing how Raman spectrum results of carbon nanotubes vary with different annealing temperatures. As the temperature condition of the high-temperature annealing increases, the decrease of the D-band can be confirmed.

Nevertheless, the reason why the high-temperature heat treatment is performed by setting the temperature condition of step S100 at 1,500 ° C. to 1,750 ° C. is that the high-temperature paste is produced by a high- This is because it is judged as a temperature for realizing the optimum electric conductivity with respect to the cost to enter the time.

2. Composition mixing step < S200 >

In this step, a heat-treated nano-carbon-based conductive filler, a binder and a solvent are mixed through a high-temperature heat treatment step (S100).

Here, the composition ratio of the composition to be mixed is 1 to 10 parts by weight of the heat-treated nano-carbon-based conductive filler, 1 to 40 parts by weight of the binder, and 1 to 40 parts by weight of the solvent.

Further, the binder which is mixed to facilitate dispersion in a nanocarbon-based conductive filler having substantial properties of a high-conductivity paste and to provide an adhesive force so that the paste is stably positioned in the material to be applied and the film is formed, But it is not limited thereto.

The solvent may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dichloroethene, toluene, N, N-dimethylformamide, N-methyl Methylpyrrolidone, but can be selected without limitation as long as it can function as a dispersion solvent and can melt the binder.

3. Ultrasonic Processing Step < S300 >

In this step, a process of performing ultrasonic processing on the mixed composition through the composition mixing step (S200) is performed. This process is done to further activate dispersion of the nanocarbon-based conductive filler in the mixed composition, and the ultrasonic waves are processed for 4 hours at a maximum output of 350 W at a frequency of 40 Hz.

4. Stirring step < S400 >

In this step, the ultrasound-treated composition is agitated through a dispersing impeller at a speed of 500 RPM to 600 RPM for 30 minutes to 60 minutes through an ultrasonic treatment step (S300). In this case, the stirring speed is set to 500 RPM to 600 RPM and the stirring time is set to 30 minutes to 60 minutes, so that the dispersed carbon nanotubes of the conductive carbon nanotubes of the conductive carbon nanotubes are aggregated and entangled with each other, So that the carbon structure is not damaged and electrical characteristics are not reduced.

In this process, each composition should be uniformly mixed through a dispersing impeller in which a plurality of blades are rotated, and a suitable emblem shape should be selected according to the viscosity of the high-conductivity paste to be produced and the kind of the composition.

5. Milling step < S500 >

In this step, a uniformly mixed composition is milled through a 3 roll mill through a stirring step (S400). Here, the degree of dispersion is determined by the pressure of the roll used for milling and the rotation ratio between the rolls.

Among the compositions of the high conductive paste, the nanocarbon-based conductive filler is a structure based on carbon as a basic unit, and these structures interact with each other by a strong van der Waals force to easily aggregate.

The nanocarbon-based conductive filler thus aggregated can not be expected to function as a filler to exhibit mechanical, electrical, or thermal properties in an object coated with a high-conductivity paste. Therefore, in order to disperse the aggregated carbon structures, (S300), a stirring step (S400), and a milling step (S500).

Through such a process, the produced high-conductive paste can exhibit sufficiently high conductivity even with a small amount of nano-carbon-based conductive filler, and it is possible to provide a high- And by recovering and improving the crystallinity through the high-temperature heat treatment step (S100), it becomes possible to manufacture a high conductivity paste irrespective of the damage of the carbon structure of the nanocarbon-based conductive filler.

In general, the conductive paste is used for forming a surface heating element, and the sheet resistance range of the surface heating element can be measured to compare the electrical environment for inducing the temperature rise of the surface heating element. The electrical environment is consequently the electrical resistance of the used conductive paste It becomes a standard for judging the electric conductivity.

FIGS. 4 and 2 are graphs showing surface resistivity test results of the surface heating element manufactured using the high conductive paste of the present invention. The carbon nanotubes used as a conductive filler based on a nano-sized carbon The surface resistance of the surface heating element coated with the high conductivity paste can be confirmed.

Treatment temperature (캜) Sheet resistance (ohm / sq) Error rate 0 28.18 5.0086 1,500 24.37 0.7148 1,750 22.3 0.71 2,000 21.5 0.75 2,500 21.2 0.7 2,800 21 0.4

As shown in FIGS. 4 and 2, in the case of the high-conductivity paste prepared according to the embodiment of the present invention, compared to the conventional paste prepared by using the carbon nanotubes not subjected to the heat treatment, the surface resistance Is reduced to 22.3 ohm / sq.

As shown in FIG. 4 and Table 2, it can be seen that the error rate of the sheet resistance and the sheet resistance decreases sharply as the heat treatment temperature increases. As the heat treatment temperature becomes 1,750 ° C., the decrease rate of the sheet resistance decreases It can be seen that when the temperature is more than 2,000 DEG C, almost no change in the sheet resistance is observed.

That is, when the temperature condition of the high temperature heat treatment step (S100) of the nano carbon based conductive filler is applied at 1,750 or more, the high conductivity through the recrystallization of the nanocarbon structure, the thermal decomposition of the non-carbon molecule and the oxidation of the amorphous carbon The cost and time for realizing the high temperature conditions for the improvement of the characteristics of the elements are considerably inefficient.

Also, when the high-temperature heat treatment step (S100) is applied at 1,500 占 폚 or less, recrystallization of a nano-carbon structure to realize sufficient high-conductivity characteristics with only 1 to 10 parts by weight of a conductive filler based on nano- Pyrolysis of carbon-based molecules and oxidation of amorphous carbon are not sufficiently achieved.

Conventionally, a conductive paste is prepared by mixing a highly conductive nano carbon based filler such as a carbon nanotube with a high content of a filler or by adding a metal material to the composition in order to lower the electrical resistance of the produced high conductive paste and to improve the electrical conductivity.

In this case, the high content of carbon nanotubes can greatly improve the resistance of amorphous carbon in the paste and change the viscosity of the prepared paste itself, resulting in a lower viscosity. Further, the addition of the metal material may cause various problems such as a change in resistance due to oxidation of the metal.

However, in the case of the present invention, it is possible to prevent the resistance change due to metal oxidation from occurring even after the conductive paste is applied to the specific material by excluding the addition of the metal material, and by increasing the carbon crystallinity by conducting the heat treatment at high temperature of the nano- , It is possible to have a low electric resistance by only the content of 1 to 10 parts by weight so as to not only increase the cost efficiency of the filler used in the production of the high conductivity paste but also solve all of the conventional problems described above.

As a result, the surface heating element manufactured using the high conductive paste of the present invention is formed so as to realize heat generation in a low voltage environment of 24V. The surface heating elements made with conventional pastes had a resistance of 10 ohm (sheet resistance of 30 ohm / sq), so that the heating time with current less than 1A took more than 10 minutes. However, the planar heating element manufactured using the high conductive paste of the present invention can exhibit various heating rates through a current of 1.5 A or more by forming a resistance of 4 ohm (sheet resistance of 25 ohm / sq).

The embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention. The scope of protection is to be construed in accordance with the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

Claims (10)

A step of heat-treating a nano-sized carbon-based conductive filler at a temperature of 1,500 ° C to 1,750 ° C in a vacuum state;
A step B of mixing the heat-treated nanocarbon-based conductive filler, a binder and a solvent;
A step C for performing ultrasonic treatment on the composition mixed in the step B;
Stirring the ultrasonic treated composition through a dispersing impeller; And
And Step E in which the composition stirred in Step D is milled through a 3 roll mill.
A method for producing a high conductivity paste by high temperature heat treatment.
The method according to claim 1,
The composition to be mixed in the step (B)
1 to 10 parts by weight of the heat-treated nanocarbon-based conductive filler;
1 to 40 parts by weight of the binder; And
And 1 to 40 parts by weight of the solvent
A method for producing a high conductivity paste by high temperature heat treatment.
The method of claim 2,
The nanocarbon-based conductive filler may be selected from single wall carbon nanotubes, double wall carbon nanotubes, multi wall carbon nanotubes, graphite, fullerene, (Fullerene), carbon black (Carbon Black), and carbon fiber (carbon fiber).
A method for producing a high conductivity paste by high temperature heat treatment.
3. The method of claim 2,
Wherein the binder is provided with a polymeric material of polyester system
A method for producing a high conductivity paste by high temperature heat treatment.
3. The method of claim 2,
The solvent may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dichloroethene, toluene, N, N-dimethylformamide, (N-methylpyrrolidone). &Lt; RTI ID = 0.0 &gt;
A method for producing a high conductivity paste by high temperature heat treatment.
The method according to claim 1,
In the step D, the dispersion impeller is stirred at a speed of 500 RPM to 600 RPM for 30 minutes to 60 minutes to uniformly mix the composition
A method for producing a high conductivity paste by high temperature heat treatment.
1 to 10 parts by weight of a conductive filler based on a nano-sized carbon;
1 to 40 parts by weight of a binder; And
1 to 40 parts by weight of a solvent,
Wherein the nanocarbon-based conductive filler is heat treated at a temperature of from 1,500 ° C to 1,750 ° C in a vacuum state
High conductivity paste composition.
The method of claim 7,
The nanocarbon-based conductive filler may be selected from single wall carbon nanotubes, double wall carbon nanotubes, multi wall carbon nanotubes, graphite, fullerene, (Fullerene), carbon black (Carbon Black), and carbon fiber (carbon fiber).
High conductivity paste composition.
8. The method of claim 7,
Wherein the binder is provided with a polymeric material of polyester system
High conductivity paste composition.
8. The method of claim 7,
The solvent may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dichloroethene, toluene, N, N-dimethylformamide, &Lt; RTI ID = 0.0 &gt; N-methylpyrrolidone. &Lt; / RTI &gt;

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