Applications and requirements
Thermal conductive pastes are used wherever electronic components need to be cooled efficiently and disruptive ambient conditions must be completely eliminated. The automotive and electrical industries, as well as numerous other sectors, use the ability of thermal conductive pastes to efficiently dissipate the heat generated from power electronics. A common application is increasing energy densities in batteries in the field of electromobility, as well as for other moblity applications.
As the demands on thermal conductivity continue to rise, a higher proportion of filler is increasingly being introduced into the formulation. These fillers are optimized by the material manufacturers in terms of their particle size distribution and geometric surface properties for efficient heat transfer. The insulating property of the surrounding plastic should exert as little influence as possible on the thermal conductivity. Typical fillers for thermally conductive pastes are aluminum oxide and boron nitride, which are also used in grinding pastes due to their hardness grades. In addition to the ceramic filler classes, formulations with metal particles are also used, especially in applications that require electrical conductivity at the same time.
In addition to the polymer matrix and the fillers, special additives are used to control the rheological properties and the wettability of the fillers. These influence the function as well as the processability of the formulation. The low proportion of polymer matrix in the presence of fillers, some of which are highly abrasive, poses particular challenges for the system design and the dispensing components used. High maintenance costs and plant downtimes must be avoided.