Extrusion International 6-2023

52 Extrusion International 6/2023 RECYCLING – CASE STUDY “Companies like Prof Sentetik are real pioneers on the packaging market”, said Harald Neumüller, Sales Direc- tor at Starlinger. “With their technical competence and future-oriented mindset they drive the market toward a sustainable circular economy. A closed packaging loop for big bags works well if the big bags are made for re- cycling – meaning that they are designed and produced with recycling in mind and thus can be recycled easily at the end of their use phase. The better the recyclate quality, the higher can be the recycled content in the newly produced big bag”, explained Neumüller. To be able to use a high share of recycled content in big bags, it is important to follow the rules for Design for Recy- cling (DfR) which are summarized in a guideline estab- lished by EFIBCA, the European Flexible Intermediate Bulk Container Association. The guideline focuses main- ly on the mono-material principle by reducing foreign materials in sewing yarns, belts, additives, inks, etc. used for big bag production. Prof Sentetik currently processes in-house production waste and additionally buys recycled PP granulate, pro- duced also frompost-consumer plastic packagingwaste. “As big bags have to meet special safety standards, the quality of the recycled material plays an important role in tape production”, confirmed Fahri Şengül. “The Starlinger tape extrusion line with the eqoCLEAN filter module ensures that the tapes we produce meet the specifications regarding tensile strength and elonga - tion required for big bags in heavy-duty applications.” Melt filtration – a must when processing recycled materials The extrusion of heavy-duty PP tapes with recycled content, especially from recycled post-consumer plastic waste (PCR waste), requires adequate melt filtration. The share of rPP materials which can be processed de- pends on various factors, for example fromwhich waste stream the post-consumer waste comes from, or how the waste was handled during collection and storage. Fine filtration already before tape extrusion, i.e. dur - ing the recycling process, is crucial. Solid contaminants which can occur in PCR materials, as well as foreign poly- mer particles in the melt – e.g. from polyester sewing yarn – compromise tape quality and cause problems in the tape production process. The eqoCLEAN filter module developed by Starlinger takes into account all the requirements for producing high-quality PP tapes with post-consumer recycled PP. It consists of a SPB single-piston power-backflush filter, a melt pump, and a second filter unit, called HS 2.0 fil - ter. The SPB filter has one piston and four cavities for filter screens and can be used for processing polyole - fins such as PP or PE. During the hydraulic power-back - flush procedure the line operates at full production speed without interruption of the production process. The regular automatic high-pressure backflushing pro - cedure cleans the filter screens throroughly, increasing their lifetime and reducing machine downtime signifi - cantly. The melt pump in combination with the addi- tional HS 2.0 filter, which is positioned directly before the extrusion die, ensure stable production and high operational reliability of the line. It also enables the processing of high shares of CaCO 3 and post-consumer recycled PP of 50 % and more. Following the tape production process, the tapes are wound onto bobbins and turned into big bag fabric on Starlinger’s heavy-duty circular looms. In the last step, the woven fabric is converted to big bags. Properties such as tensile strength, weight and safety factor of Prof Sentetik’s big bags with rPP content meet all required safety standards and are continuously tested using stan- dard testing procedures and certified equipment. “We are very satisfied with how things are going”, said Fahri Şengül. “We even aim to increase the recycled content in our big bags to 50% and more. Also, we are considering to install our own Starlinger plastics recy- cling line – it can be the first step towards establishing a closed packaging loop for big bags here in Türkiye with our local big bag users. We have to think about our en- vironment and take care of nature. We all – consumers, manufacturers and equipment suppliers – must work together to stop the destruction of the environment.” Prof Sentetik https://profsentetik.com/en// Starlinger & Co Ges.m.b.H. Sonnenuhrgasse 4, 1060 Vienna, Austria www.starlinger.com Fahri Şengül, General Manager of Prof Sentetik, aims to include 50 % and more rPP in FIBCs – also in order to meet government regulations such as the UK Plastic Packaging Tax which came into force in 2022