Novel Spherical Copper Two-Component Self-Curing Adhesive for Heterogeneous Bonding Conductive Thermal Device Application with Carbon Dioxide Reduction
Authors: Chen Yen-Shuo , Huang Yi-Cheng , Lin Ching Chang , Ko Ching-Chung , Lin Jung-Chin 
Published: December 2024

This study is dedicated to the development of a two-liquid spherical copper-based adhesive designed to optimize the metal joining process to achieve environmental goals, simplify operational steps, and reduce manufacturing costs. Conventional metal joining methods, such as soldering and chemical plating, are not only cumbersome and energy-consuming in terms of steps, but also cause serious environmental problems, including high carbon emissions and the generation of hazardous plating wastewater, which is costly to treat. The two-liquid spherical copper-based adhesive proposed in this study is intended to replace these conventional techniques and solve the above problems through a more environmentally friendly and cost-effective bonding method. This innovative bonding technology not only reduces the environmental impact, reduces the process flow of metal joining, and lowers the production cost.

First, the two-liquid spherical copper-based adhesive used in this experiment was cured by room temperature curing. Adhesive refers to the substance that can realize the connecting effect of materials, also known as adhesive or bonding agent.

After the adhesive is applied to the surface of the substrate, a certain curing process is required to achieve the bonding of the substrate. This process involves a chemical reaction that hardens the adhesive and forms a strong bond between the two surfaces.

In this study, we performed cure time and thickness measurements using a two-liquid spherical copper-based adhesive. two-liquid spherical copper-based adhesive was able to cure in 45 minutes at 40°C. We measured the thickness of the two-liquid spherical copper-based adhesive and the results showed an average thickness of 25 µm. This data provides an important reference for this experiment.

In Figure 1, a tensile test of a metal sheet is shown. The results show that the metal sheet coated with the two-liquid spherical copper-based adhesive had a tension of 208 N in the tensile test. This demonstrates the excellent torsional properties of the adhesive in bonding technology., including significant shear strength.

Next, a thermal conductivity test was conducted. After keeping the heating plate at 100°C, the metal sheet shown in Figure 2, coated with a two-component copper-metal adhesive, was placed in a 100°C temperature environment for 5 minutes. The test results showed that the temperature of the sheet metal remained at 32°C. This may be due to the adhesive being applied to the metal sheet. This may be due to the excellent thermal conductivity of the adhesive, which can quickly transfer heat from the surface of the sheet metal to the surrounding environment so that the temperature of the surface of the sheet metal is consistent with that of the surrounding environment. In addition, the two-liquid copper-metal adhesive for heat transfer coefficient has been verified by a third party (TECHMAX TECHNICAL CO., LTD) with a thermal conductivity of 87W/mK. This result further confirms the excellent performance of the adhesive in terms of thermal conductivity.

This result further validates the excellent performance of the adhesive in terms of thermal conductivity. Finally, the two-liquid spherical copper-based adhesive was applied to the AI server for adhesion testing. First, the hot plate was heated to 100°C and then the server was left to stand for 10 minutes. During this period, the temperature of the server shown in Figure 3 increased from the initial 33°C to 38°C and remained stable for the next 10 minutes. This process demonstrated the excellent thermal conductivity of the two-liquid spherical copper-based adhesive used. Eliminates the need to heat the process to cure the adhesive and significantly reduces carbon emissions.

The two-liquid spherical copper-based adhesive used in this experiment formed a strong bond after natural curing on the bonded surface, and at the same time had excellent heat resistance, high viscosity, and abrasion resistance. Excellent heat dissipation characteristics can be utilized in high power consumption component-to-component adhesives. This type of adhesive is not only excellent in terms of bond strength but also plays an important role in various industrial applications.

Figure 1