KR-20260067454-A - Carbon nanotubes pastes and Surface heating elements comprising the same

Abstract

The present invention relates to a carbon nanotube paste for heating elements comprising carbon nanotubes, and more specifically, to a paste with improved printability and adhesion and excellent heat resistance, as well as to a printed pattern and a heating element formed therefrom. The present invention provides a carbon nanotube paste that satisfies all of the above characteristics by utilizing an ultrasonic process and additives. Furthermore, the high-temperature stability of the heating material is significantly improved by the additives.

Inventors

• 신권우
• 김희창

Assignees

• 한국전자기술연구원

Dates

Publication Date

20260513

Application Date

20241105

Claims (10)

1. A carbon nanotube paste prepared by mixing a carbon nanotube dispersion containing a dispersant in a concentration range of 1 to 10% and carbon nanotubes in a concentration range of 5 to 10%, and an AZC (Ammonium zirconium(IV) carbonate) solution containing Zr in a concentration range of 13 to 22%, in a volume ratio of 10:0.3 to 10:2.
2. In paragraph 1, A carbon nanotube paste characterized by performing ultrasonic dispersion to prepare the above carbon nanotube dispersion.
3. In paragraph 2, A carbon nanotube paste characterized by the above ultrasonic dispersion being performed by adding carbon nanotubes in two or more separate steps.
4. In paragraph 1, A carbon nanotube paste characterized in that the above-mentioned dispersant is Poly(sodium 4-styrenesulfonate) or Poly(sodium 4-styrenesulfonic acid).
5. In paragraph 1, A carbon nanotube paste characterized by maintaining the dispersion state of the carbon nanotube dispersion when the above carbon nanotube dispersion and the AZC solution are mixed.
6. In paragraph 1, A carbon nanotube paste characterized by the fact that the carbon nanotube dispersion further comprises one or more selected from the group consisting of carbon black, graphene, and graphene nanoplates (graphite nanoplates).
7. In paragraph 6, A carbon nanotube paste characterized in that, in the above dispersion, carbon nanotubes are in a concentration range of 4 to 10%, and carbon black, graphene, or graphene nanoplates (graphite nanoplates) are in a concentration range of 5 to 10%.
8. A printed pattern formed from a carbon nanotube paste according to any one of claims 1 to 7.
9. In paragraph 8, A printed pattern characterized by using a screen printing method to form the above printed pattern.
10. A heating element including the printed pattern of claim 8.

Description

Carbon nanotube pastes and surface heating elements comprising the same The present invention relates to a carbon nanotube and zirconium composite paste for a heating element comprising carbon nanotubes, and to a carbon nanotube paste having improved printability and adhesion and excellent heat resistance, and a printed heating element using the same. Carbon nanotube (CNT)-based heating paste is a material that converts electrical energy into heat by utilizing the excellent electrical and thermal conductivity of CNTs. It is used to manufacture thin, flexible heating films or planar heating elements. The paste for heating elements using carbon nanotubes is an organic paste in which the solvent is mainly an organic solvent, and is composed of carbon nanotubes, a dispersant, an organic solvent, a binder, etc. In the manufacture of carbon nanotube paste, uniform dispersion is important, and agglomeration of carbon nanotubes must be prevented during the manufacturing process. It is manufactured by dissolving a binder in an organic solvent, adding a dispersant and carbon nanotubes, and high-pressure dispersion using a 3-roll mill or similar equipment. This method utilizes the principle that carbon nanotubes are dispersed by the high viscosity of the binder and the rotational shear force of the 3-roll mill. However, this method incurs high processing costs, and it is generally difficult to achieve low resistance because it is difficult to disperse carbon nanotubes in a high concentration within the paste. On the other hand, the method using water as a solvent and ultrasound has the advantage of enabling carbon nanotube dispersion without a binder and obtaining a carbon nanotube dispersion through a simple ultrasonic process. However, such water-based dispersions have low viscosity and high surface tension, making them unsuitable for printing by screen printing methods, and the adhesion of the printed heating material is generally weak, and the heating material deteriorates quickly at high temperatures. In Korean registered patent No. 10-2049266, a conductive composition containing CNTs and graphite particles was developed, and thermal conductivity and stability were improved by mixing a binder such as phenolic resin and epoxy acrylate. Korean Patent No. 10-1524642 describes the application of a mixture of carbon nanotubes and other conductive particles to a portable heating heater that operates even with low power. Figure 1 illustrates the screen printing plate and printing pattern used in Example 1. Figure 2 illustrates the printing pattern of Example 2. Figure 3 shows the printing pattern of Comparative Example 1 and the 3M tape peel test results. Figure 4 shows the peel test results when the pattern formed from the paste prepared in Examples 1, 2 and Comparative Example was exposed to high temperature. FIG. 5 is an example of a heating element including a printed pattern formed from the paste of the present invention. The present invention relates to a carbon nanotube printing pattern and a heating element comprising the same, wherein the carbon nanotube paste is prepared using an ultrasonic dispersion method and the carbon nanotube paste has excellent screen printing properties and improved adhesion and heat resistance of the printed heating material. To this end, the present invention is characterized by adding a specific additive to the carbon nanotube dispersion to improve screen printing properties, adhesion, and heat resistance. Carbon nanotubes are long, crystalline nanocarbon particles in the shape of tubes, with a diameter of 1 to 100 nm and a length of 1 to 100 µm, and are carbon-based nanoparticles with a large aspect ratio. They exist as single-walled or multi-walled carbon nanotubes, which are determined by the number of walls constituting the tube. As carbon nanotubes are nanoparticles with excellent electrical conductivity, they can be manufactured in a paste form by dispersing them well. Pastes are primarily viscous materials that are printed onto a substrate in various patterns through a screen printing process to form conductive printed patterns. Heat is generated when electricity is passed through a printed carbon nanotube pattern, and planar heating elements can be manufactured using this principle. The heating temperature and output of the heating element are determined by the resistance and voltage of the paste-printed pattern; generally, higher heating temperatures and outputs can be achieved as the resistance of the printed pattern decreases and the voltage increases. Furthermore, ensuring heat resistance is crucial for the paste-printed pattern to be used as a high-performance heating element. By ensuring the stability of the heating material at high temperatures, the heating temperature of the heating element can be further increased. In the manufacture of carbon nanotube paste, additional carbon particles can be added to further increase the carbon particle content and lower the resis