Extrusion International 4-2020

42 Extrusion International 4/2020 EXTRUSION TECHNOLOGIES, RECYCLING on the filter fineness, and allow fully automatic produc- tion without the need for personnel for several weeks. Retrofit extruder allows food contact There are many factors involved in the processing of PET in general, and of recycled material in particular. In addi- tion to the mechanical cleaning of the melt by the filtra- tion system, the extruder has the task of thermal clean- ing. Here, the processing unit should work gently in order to exert as little mechanical stress as possible on the sensi- tive polymer. Through simultaneous vacuum degassing, low-molecular components such as monomers, oligomers or decomposi- tion products can be removed from the plastic melt on the one hand, while on the other hand moisture escapes here, which would initiate chain degradation and thus viscosity reduction. Finally, even more happens in the vacuum zone: contami- nants that can never be ruled out in recycled goods, such as solvents, stabilizers, acetaldehyde scavengers or oils, must escape. All these functions are combined in the Gneuss Multi- Rotation System (MRS) extruder based on a single screw extruder. This extruder processes PET melt gently and provides a particularly large melt surface in the multi- screw section with degassing zone. In this way, even with a simple vacuum of 25 to 30 mbar an enormous de- gassing and decontamination performance is ensured. Reason enough for the American FDA authority to grant Gneuss MRS Extrusion Technology a Letter of Non-Ob- jection. As well as in Europe, where the Gneuss recycling process received EFSA approval for the processing of 100 % post-consumer PET on thermoforming sheet pro- cessing line. Convincing arguments for many customers The above-mentioned advantages of the MRS extruder not only convinced the Argentinian customer Cotnyl, the first company in the country to produce packaging made of 100% recycled material, but also many other proces- sors. One of them is Integrity from Chile, which, after purchasing the filtration systems from Germany, has now also opted for an extruder from Bad Oeynhausen. Integ- rity was thus able to increase the proportion of recycled material in the PET thermoformed trays to up to 100 %. A perfect retrofit solution. Online Viscometer completes retrofit solutions A manufacturer in South America has decided, in addi- tion to the MRS 130 with a capacity of around 1,000 kg/h, to purchase a complete Gneuss Processing Unit which in- cludes an RSFgenius 150 as well as an Online Viscometer. The latter is also available separately and is ideal as a ret- rofit solution. It measures a small partial flow of the melt during ongoing production and determines melt temperature and pressure via a precisely manu- factured slit capillary. Based on internal calculations, the online vis- cometer constantly provides the representa- tive shear rate and dynamic viscosity. Depend- ing on the values determined, the vacuum in the degassing zone of the MRS extruder is read- justed to keep the melt viscosity within the speci- fied tolerances. Regardless of which key component, MRS extruder, melt filtration system or online viscometer, a processor choos- es, the ability to process recycled material and still pro- duce high-quality PET sheet is therefore possible. In com- bination with Gneuss’ consulting services, an optimum solution can be found for almost any application. Gneuss Kunststofftechnik GmbH Moenichhusen 42, 32549 Bad Oeynhausen, Germany www.gneuss.com Retrofit solution in Southamerica MRS Extruder withmulti-rotation sector