Coperion Holding GmbH will present its two-stage compounding extruder, called ZSK-NT, designed for compounding bimodal polyethylene.
Bimodal PE contains short polymer chains for processability and chains of high molecular weight for good properties. Applications for the material include PE pressure pipe, film, tubes, filaments or blow molded packaging.
During compounding, the powdery raw polymer is turned into pellets, and Stuttgart-based Coperion said two process steps are critical: the melting of the polymer without overheating and the homogenization of ingredients that have different viscosity levels.
The ZSK-NT separates those two steps for the first time, so they can be optimized independently. The first, relatively small ZSK compounder gently melts the PE powder, with a low energy input at a high screw speed. Then the melt is transferred to the larger, slower-rotating homogenizing extruder.
Specially developed screw elements handle the bimodal PE correctly, creating pellets that can be easily processed without additional homogenization.
Also in Dusseldorf, Coperion will show the ZSK MegaCompounder PLUS, a high-torque machine now with even more torque, thanks to an increase in the specific torque at the screw shafts. Coperion will reveal technical details of the machine, which increases throughput by 20 percent, for the first time at K 2004.
In other news, the company will introduce a laboratory extruder, the ZSK 26 Mc. For the first time, a compounding company can use data from the lab machine to do a direct scale-up to a ZAK MegaCompounder, because the screw and drive of the small machine are designed to the same key data, such as diameter ratio.
Coperion's bulk material-handling unit, Coperion Waeschle GmbH & Co. KG, will show a new gravitation blender for powders, using a fluid cone blender design; the ZAG series of discharge valves, also for power; and a compact tubular heat exchanger called Bulk-X-Change.
Coperion Holding's U.S. headquarters, Coperion Corp., is based in Ramsey, N.J.