These specific characteristics are programmed at the compounding stage, often using a combination of reinforcing agents, fillers, flame retardants and other additives. Compounding polyamides is therefore very demanding and requires customized solutions accordingly. These solutions are given with the BUSS polyamide compounding systems. Specific energy inputs have to be as gentle as possible, large amounts of fillers and flame retardants have to be perfectly distributed, and reinforcement fibres must be added so as to optimize mechanical properties while at the same time maintaining high dwell times in the respective process zones.
Although contradictory in part, all these requirements are well mastered by sophisticated process technology. The BUSS Kneader has proven itself again and again for compounding such highly demanding materials. This is mainly because of its moderate and uniform shear rates, which can be customized, if necessary, to ensure precise temperature control. As a result, just enough energy is dissipated in the melting zone to avoid overstressing the polymer fractions. Thanks to high folding rates, the fillers and flame retardants are optimally distributed over the shortest possible processing length. The reinforcement fibres added, if necessary, downstream are separated and sheathed in order to preserve maximum fibre length. Even with the narrowest process window such as for PPA based materials, with only 30°C temperature margin between melting and incipient breakdown. it is possible to achieve the best characteristics profile also at the highest viscosities.