Extrusion International 4-2018

28 Extrusion International 4/2018 EXTRUDER, RECYCLING tifiable, volumes are substantial and the market proves to be receptive concerning its reuse. Polymers as polyethylene (PE) and polypropylene (PP) can be recycled showing satisfactory results. Poly- ethylene terephthalate (PET) from bottles, which is an example of MSW polymers, has a rather clear composi- tion, it can be easily selected and its reuse for the production of bottles in the food sector has recently been au- thorized. When recovering the PET, it is manda- tory to reduce water traces so as to minimize the loss of intrinsic viscos- ity; for that reason, the process re- quires the use of high vacuum pumps enabling the removal of the residual moisture from the material and avoid any decrease in performances. Other sources of post-consumer ma- terial derive from the agricultural sec- tor (e.g. the mulching film) and from the automotive sector, especially ma- terials coming from wreckers. In the first case, the resulting and remark- able quantity of reusable high-den- sity polyethylene (HDPE) can be em- ployed for the same application (even if rather polluted by rubble and dirt); as for the second case, we have large volumes of different materials with a discreet traceability. In the past, Maris has carried out some tests reprocessing hygiene-re- lated items (namely diapers) with a PE polymer base. Materials of this nature can be found in big amounts and have shown some cleaning and sanitation- related difficulties, as well as concern- ing their feeding into the extruder. Furthermore, even ‘printed polyole- fins’ from food packages can be dis- colored thanks to the stripping tech- nique, which is typically carried with water. Industrial scraps – if appropriately se- lected – provide an excellent second- ary raw material (SRM). In the rubber sector, for example, thanks to the devulcanization process patented by Maris, which makes it possible to recy- cle production wastes through a con- tinuous system, producers can reuse part of their wastes re-introducing recycled rubber into the same produc- tion cycle in a proportion that does not compromise the material perfor- mances. In fact, the devulcanization process enables the reintroduction of recycled material into the basic formulations from 15% to 50% mini- mizing the impact on the mechanical properties of the final product. It should be underlined that – after a careful selection and the identifi- cation of materials – the abovemen- tioned devulcanization process can be applied to post-consumer materials as well. In this case, recycled rubber can be employed in completely different areas when compared to those of ori- gin. Back to industrial wastes, thermo- plastic materials offer a wide range of possibilities. Processing wastes and non-compliant parts – once ground and converted into free-flowing ma- terial – are likely to be mixed with sol- id and/or liquid additives to be then reused. This type of process can be applied to all types of polymers (such as polyole- fins and PVCs) and techno-polymers (including TPUs and PCs). Industry 4.0: What’s new? The term ‘Industry 4.0’ has now be- come an expression of common knowledge, even though a widely shared definition or a specific rele- vant legislation still does not exist. The word was born in Germany in 2013 to be then interpreted in several and rather different ways according to the most diverse realities and specificities of the countries where it has been adopted. Industry 4.0 is a ‘paradigm’ or – rather – a ‘concept’ able to turn the production reality into a leaner, dynamic, flexible, efficient and sus- tainable system thanks to specific principles (e.g. interconnection and/ or virtualization). In other words, it is the process that will lead users to a fully automated and interconnected industrial production. Criteria for its application vary accord- ing to the country of reference. Com- mon standards are particularly difficult to identify. As for the Italian legislation, the ‘general guidelines’ applied to the extrusion lines are the following: