These specific property profiles are achieved by compounding in precise compliance with very demanding requirements. Conductivity must be guaranteed both at room temperatures and under hot operating conditions. The added soot or carbon black, graphite, carbon nanotubes and carbon fibres must retain their complex structures and be distributed extremely homogeneously to form a dependable conductive network. The polymers used must be broken down as little as possible. Crosslinkability of the compounds can also be a requirement.
These sometimes-conflicting requirements are well controlled by sophisticated techniques. The BUSS Kneader has proven itself time and time again in compounding these particularly demanding materials. Its moderate and uniform shear rates, specifically adaptable for precise temperature control, play the central role thereby. In the melting zone, as much energy as necessary is dissipated without overstraining the polymeric components. The conductivity agents are distributed optimally within the shortest process length thanks to high folding rates. Downstream, the appropriate conductivity fibres are added, singulated and enveloped to preserve the maximum lengths required for their role in the conductive network. Optimal property profiles can thus be achieved even in the narrowest process windows at highest viscosities.
With the two-stage BUSS Kneader system, the compounding and pressure build-up steps are consistently decoupled from each other. They can therefore be optimized independently. Furthermore, the hinged housing of the BUSS Kneader ensures fast access and high system availability. Together with the broadly based Buss process expertise, the modular and thus adaptable design of the entire system make the BUSS Kneader an excellent investment choice for compounding these demanding high-conductivity compounds.