Extrusion International 5-2019

26 Extrusion International 5/2019 EXTRUSION TECHNOLOGY Innovations for Compounding and Recycling The central position in the MAS range continues to be the conical twin-screw extrusion system with co-rotating screws introduced in 2007. Its peculiarities and the ad- vantages derived from it are the gentle plasticizing, even conveying and good homogenization at high throughput. Measurements of the physical extrudate characteristics show that they are maximally preserved compared to the input qualities when processing on MAS extruders, which is particularly important for recycling applications. Due to the large cross-section of the feed opening and the result- ing feed volume, the MAS extruders are particularly suit- able for materials with low bulk density, such as recycled flakes, but also for use in compounding technology. An important advantage for plastics recycling is the high plas- tification quality, which provides the ideal conditions for efficient removal of foreign matter through filtering and degassing. The MAS extruders are available in six sizes in an output range of 10 to more than 2,000 kg/h (Picture 1). Their coni- cal screws have a modular structure and thus can be adapt- The Upper Austrian “MAS Maschinen- und Anlagenbau Schulz GmbH”, inventor and established supplier of the conical co-rotating twin-screw extruder system, will introduce two new innovations for the compounding and the recycling technology beyond the twin-screw extrusion technology at the K 2019 on booth 9 / D42 Picture 1: The conical co-rotating twin-screw extruders are available in 6 size stages with a throughput ranging from 10 to over 2,000 kg / h (All pictures: MAS) Picture 2: MAS-high-quality compounding configuration consisting of a conical co-rotating twin-screw extruder as additive conveyor and a side-feeding single-screw extruder for polymer addition ed quickly and easily to the respective application. Another advantage of the MAS extruder is the plasticization with a largely constant melt pressure, setting the precondition for not requiring the use of melt pumps in almost all regranu- lation applications. New innovation for compounding glass or carbon fibers As mentioned above, one of the most important advan- tages of the conical MAS extruder is the large feed open- ing in combination with the good feed behavior of the co-rotating screw system. This provides the best conditions for an efficient intake of additives like stabilizers, fillers but also fibrous materials. In order to make the best pos- sible use of this advantage, MAS has further developed the machine concept for compounding. It supplements the MAS extruder by a single-screw extruder in sidefeeder configuration (Picture 2). Its task is to meter in the main polymer, while the large-scale feed zone of the MAS ex- truder is left to the task of additives. This configuration saves the use of individual sidefeeder along the extrusion line compared to conventional systems. The advantages are an earlier achievement of a good mixing quality and ultimately a higher compound homogeneity. These advan- tages are complemented by the above-mentioned basic MAS-advantage of very gentle plasticization, as a result of which the additives, in particular glass or carbon fibers, are subjected to only minimal mechanical stress. Their length and thus their reinforcing effect remain maximum. The system has successfully passed its test in trial opera- tion and will be open for series application fromK 2019 on. More information is available at the MAS-booth. Cascade retrofit package for recycling extruders to increase throughput, quality and profit The second MAS-fair-novelty is a retrofit package for recy- cling lines to increase the process performance and quality, especially for the processing of PE-film-flakes. It is a combi-