Production of powder for Masterbatch
The outstanding characteristic of this system, the one that distinguishes the mill from others in the market, is the capability to process hard-to-grind plastics such as EVA, ABS, SAN or PA6 without special cooling into high quality powders, for example for masterbatch and compounds. Saving energy does not only start by tweaking the constructive details but also with basic procedural issues. If the materials do not have to be excessively and expensively cooled by means of liquid nitrogen or other cooling agents, if the mill can be cleaned faster and more thoroughly and if more material can be processed in one mill and in quick succession and if the important parameters of the end product can be specifically influenced, considerable energy-, cost- and quality advantages can be achieved.
State of the art of almost any mill available on the market is that the mill can almost only process PE at ambient temperature. The cooling achieved by means of the air flow is not sufficient enough to eliminate the temperature increase incurred during the grinding of other materials and thereby requires the addition of a cooling agent. Most of the time liquid nitrogen is used, which is costly to produce, store and correctly dose. The related expense is reflected in a 5 to 10 Euro cents per kilogram in production costs. These costs can be saved by using a Pallmann Polygrinder Grinding system.
This is demonstrated in the numerous patent protected parts in the mill’s design, which allows for pulverization of difficult materials such as EVA, with an 18 to 20 percentage of VA, without additional cooling. The Polygrinder has mastered a Polypropylene-copolymer, depending on the material composition which almost none of the market available mill can process. In addition to the direct savings as a result of not using expensive liquid nitrogen, the relatively low system complexity also works to save costs.
The pulverization of a wide spectrum of plastics without additional cooling agents and to a defined particle is possible due to the specially designed grinding discs: Instead of a one piece disc the profile section of the machine is made up of key segments, which produce a scissor-type cutting across the entire width of the grinding area. This type of cut also puts less energy –and thereby less heat- into the product. This scissor-cut design is not only gentle to the material but also to the mill: Less wear extends the life of the segments considerably. In addition the segmentation allows for an easy exchange of wear parts, less set-up during re-sharpening and increased safety. The one piece disc in other machines tends to warp during heat treatment and leads to installation difficulties.