Extrusion 5-2018

33 Extrusion 5/2018 When recovering the PET, it is mandatory to reduce water traces so as to minimize the loss of intrinsic viscosity; for that rea- son, the process requires 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 material derive from the agricultural sector (e.g. the mulching film) and from the automo- tive sector, especially materials coming from wreckers. In the first case, the re- sulting and remarkable quantity of re- usable high-density polyethylene (HDPE) can be employed for the same applica- tion (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-related 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 difficul- ties, as well as concerning their feeding into the extruder. Furthermore, even ‘printed polyolefins’ from food packages can be discolored thanks to the stripping technique, which is typically carried with water. Industrial scraps – if appropriately selec- ted – provide an excellent secondary raw material (SRM). In the rubber sector, for example, thanks to the devulcanization process patented by Maris, which makes it possible to recycle production wastes through a continuous system, producers can re-use part of their wastes re-intro- ducing recycled rubber into the same production cycle in a proportion that does not compromise the material per- formances. In fact, the devulcanization process enables the reintroduction of re- cycled material into the basic formula- tions from 15% to 50% minimizing the impact on the mechanical properties of the final product. It should be underlined that – after a careful selection and the identification of materials – the abovementioned devul- canization process can be applied to post-consumer materials as well. In this case, recycled rubber can be employed in completely different areas when com- pared to those of origin. Back to industrial wastes, thermoplastic materials offer a wide range of possibili- ties. Processing wastes and non-compli- ant parts – once ground and converted into free-flowing material – are likely to be mixed with solid and/or liquid addi- tives to be then reused. This type of process can be applied to all types of polymers (such as polyolefins and PVCs) and techno-polymers (includ- ing TPUs and PCs). Industry 4.0: What’s new? The term ‘Industry 4.0’ has now become an expression of common knowledge, even though a widely shared definition or a specific relevant legislation still does not exist. The word was born in Germa- ny in 2013 to be then interpreted in se- veral and rather different ways according to the most diverse realities and specifici- ties 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 sustainable system thanks to specific principles (e.g. inter- connection and/or virtualization). In other words, it is the process that will lead users to a fully automated and inter- connected industrial production. Criteria for its application vary according to the country of reference. Common standards are particularly difficult to identify. As for the Italian legislation, the ‘general guidelines’ applied to the extru- sion lines are the following: • control by means of PLC (Programma- ble Logic Controllers); • interconnectivity with factory informa- tion systems and remote loading of ins- tructions (recipes); • automated integration with factory lo- gistics systems, supply network or other machinery of the production cycle; • simple and intuitive human-machine interface; • remote maintenance, remote diagnos- tics or remote control systems; • continuous monitoring of working conditions and process parameters through appropriate sets of sensors and the adaptability to process deviations. Maris has already provided lines enabling customers to benefit from a specific fis- cal advantage. The following solutions have been chosen: Control by means of CNC (Computer Numerical Control) or PLC (Programmable Logic Controllers) Maris extruders are equipped with cons- tantly evolving hardware and software PLCs. This allows the communication within different fieldbuses and to meet the interconnectivity requirement as