Extrusion International 4-2020

41 Extrusion International 4/2020 By the end of 2030 it should be 55 % and from 2040 on- wards all plastic packaging should be 100 % reused or re- cycled so that a closed cycle is achieved. The market is already responding: according to a recent report by the British consultancy firm Eunomia, consump- tion of r-PET in the EU in 2018 was around 1.4 million tonnes, accounting for 26% of the total demand for PET of 5.3 million tonnes. By 2030, experts expect an increase in demand for r-PET of up to 55%. Approximately 20 % of the existing r-PET is used for PET trays throughout Eu- rope, with the average proportion of recycled material already at 50 % - and the trend is rising. Retrofit as an economic alternative to new investment This increased use of recycled materials poses problems for many packaging manufacturers. A recycling rate of up to 100% and the required recyclable design do not al- ways meet the requirements for packaging, especially for food packaging. Food authorities and consumers expect the highest qual- ity in terms of colour, purity, odour and mechanical prop- erties. The desired properties often cannot be achieved with existing equipment designed for processing virgin materials. Investments in completely new lines, with which the processing of recycled materials is successful, are not always possible for economic or space reasons. An interesting alternative is the Gneuss retrofit. Filtration system indispensable for high contamination levels Gneuss has already proven to many customers worldwide that retrofitting is a good alternative for processing re- cycled materials. For example, a company from South- america has been using Rotary Filtration Systems from Bad Oeynhausen for several years now to produce PET thermoformed trays with a 70% recycled content. Thanks to the patented filter disc technology, Rotary Filtration Systems operate continuously, with constant pressure and fully automatically. The high and fluctuating levels of contamination of the input material are a major problem in recycling process- ing. Especially due to the increasing demand for packag- ing with a high recycled content, the high-quality recycled material, which mostly come from sorted bottle fractions, have become scarce and processors have to fall back on inferior recycled materials with higher degrees of con- tamination. This has enormous effects on the filtration process. Screens get dirty faster and as screen contamination in- creases, the pressure upstream of the filter increases, which in turn can lead to temperature and viscosity fluc- tuations, and finally the available area for the melt to pass through is reduced. This is where the RSFgenius Filtration Systems with back- flushing technology fully show their advantages. The screen cleaning is carried out fully automatically during the running production process via an integrated back- flushing piston system, in which only a small portion of filtered melt is regularly shot through the dirty screen via a narrow gap by means of high-pressure pulses. The quantity required for this is freely adjustable and in practice corresponds to about 0.01 to 1 % of the throughput. This means that the loss is significantly lower than with other systems available on the market, which operate with losses of up to 5%, which on the one hand reduces the margin and on the other hand leads again to scrap production that has to be recycled or dis- posed of. Even with high degrees of contamination, the screens of the RSFgenius can be reused up to 400 times, depending Possible increase in PET sent for reprocessing by 2030, Eunomia, PET Market in Europe 2020 Gneuss extrusion unit for retrofitting recycling lines Filter disc cleaning with the RSFgenius Filtration System