Compounding these polymers is correspondingly challenging. The polymer components and, if appropriate, blend components, have to be melted gently and homogeneously without shear peaks, and the filler and flame retardant fractions must be excellently distributed. This is very demanding for the compounded technology. The reinforcing fibers must be added in such a way that the mechanical properties are maximized while at the same time ensuring long dwell times in the respective process zones.
These partially conflicting requirements are well mastered by sophisticated techniques. The BUSS Kneader has long proven itself in compounding these demanding materials. The moderate and uniform shear rates, also specifically adaptable if necessary, and thus precise temperature control of the BUSS Kneader play the key role here: in the melting zone, only as much energy as necessary is dissipated without overstraining the polymeric components. The fillers and flame retardants are distributed optimally within the shortest process length due to the high folding rates. Downstream, if necessary, the reinforcing fibers are added to them, isolated and then sheathed so as to preserve the maximum fibre lengths. Important market players rely exclusively on the specific advantages offered by the BUSS Kneader technology in this field.
The BUSS Kneader’s two-stage system systematically separates the compounding and pressure build-up stages so that each of them can be independently optimized. Together with the broad-based BUSS process expertise around the PBT and PET compounding technology, the modular and thus adaptable design of the entire system make the BUSS system an excellent choice for compounding the wide range of PET and PBT compounds.