Extrusion International 5-2022

42 Extrusion International 5/2022 K 2022 Extrusion Technology Gneuss’ MRS Extrusion Technology has proven itself as an alternative for the reprocessing of contaminated materials like polyester, polystyrene, polypropylene or polyethylenes. In combination with the highly efficient Gneuss Rotary Filtration Systems and optimized vacuum technology, cus- tomizable recycling lines tailor-made for a specific material can be engi - neered. Several Letters of Non Objec- tion (LNOs) from the FDA, EFSA con- formity and local approvals in Latin America confirm the decontamination efficiency of the technology. Samples of polypropylene tubs for food ap- plications made with 30 % post con - sumer PP and PS sheet made from 30 % post consumer PS, processed on Gneuss OMNI Recycling Machines with MRS extruders and RSFgenius filtration systems, will be shown at K. OMNI Recycling Machine for post- consumer fiber or thermoform re - claim: Gneuss will show its latest ma- chinery innovations for today’s and tomorrow’s recycling needs with a complete OMNI Recycling Machine featuring a new 3C Rotary Feeder, an MRS jump 70 extruder, a fully auto - matic melt filtration system RSF genius 90 and an online viscometer VIS, for the processing of 200 kg/h (450 lbs/h) of undried and uncrystallized polyes- ter (PET) thermoform reclaim. 3C Rotary Feeder: The newly devel- oped 3C Rotary Feeder makes it pos- sible to use low bulk density materi- als without any external processing steps. A conveyor belt feeds shred- ded reclaim material into the hopper, where a fast-rotating disc with knives cuts, compacts and pre-conditions the material. The knives add energy into the material and start the heating and degassing process before the material is automatically fed into the MRS jump extruder. MRS jump: The MRS extruder is based on conventional single screw technology but is equipped with a multiple screw section for devolatil- ization. It enables very efficient and gentle decontamination of PET, whilst achieving the requirements for direct food contact standards. The MRS ex - truder permits the processing of R-PET directly into high quality end products such as packaging sheet, strapping tape or filaments without pre-drying by using a simple and rugged vacuum system. This is achieved by means of its patented processing section. The Multi Rotation Section is a drum containing multiple satellite single screws, driven by a ring gear and pin- ion transmission. The satellite screws rotate in the opposite direction to the main screw. This disproportion- ately increases the surface exchange of the polymer melt. A large opening for venting, exposing the full length of the satellite screws, is completely under vacuum. This provides unrestricted access to the polymer melt, the surface of which is constantly replaced at an extremely high rate by the action of the satellite screws in the multiple screw section. The surface area – and the surface area exchange rate – available for de - volatilization are far greater than in other extrusion systems. As the ther - mal and mechanical stress on the poly- mer melt is minimized, PET processed on the MRS extruder has excellent op - tical and mechanical properties. The new MRS jump has a longer, modified version of the Multi Rota - tion Section, which ensures both a longer residence time of the material and more surface area exchange un - der vacuum. The longer Multi Rota- tion Section, coupled with a powerful vacuum system operating at 1 mbar, can be used to boost the viscosity of R-PET and to hold it at a stable level in spite of variations in the input ma- terial. Therefore, there is no need for any liquid phase (LSP) or solid state polymerization (SSP). With the stabi- lization and/or increase of the intrin- sic viscosity in the extrusion process, the MRS jump is especially well suited to recycling e.g. PET film waste or fi - ber reclaim – applications for which direct recycling with one single ex - trusion step was previously impos- sible due to low intrinsic viscosity or variable input viscosities. In combi- nation with Gneuss’ Rotary Filtra- tion Technology, a high melt purity Innovative Degassing and Decontamination Technologies for Demanding Recycling Applications Gneuss OMNImax Recycling Machine with MRSjump Extrusion System, Rotary Filtration System and 3C Rotary Feeder