Extrusion International 1-2022

43 Extrusion International 1/2022 ever better, there is always waste in the form of B-quality goods, caused by over-production and during start- up and retooling. Instead of simply disposing of this – in view of con- stantly rising prices for raw materi- als and decreasing availability – nev- ertheless valuable material, it is far more economical to process it and return it to the production process. Yarn manufacturers can not only cut costs, they also become more auton- omous. Furthermore, general devel- opments, such as increasing popula- tion densities and fast fashion, are creating ever greater demand for polyester and polyester fi bers. Here, many major textiles manufacturers have set themselves ambitious tar- gets with regards to the utilization of recycled fi bers. So, you can now see that the potential bene fi ts of fi ber recycling are tremendous. So, VarioFil R/R+ was a huge mile- stone for BB Engineering. You are now expanding your portfolio with the VacuFil. What exactly is the Va- cuFil and how does this system differ from the VarioFil R/R+? Matthias Schmitz: The starting point for the VacuFil was the aim of offer- ing our clientèle a zero-waste spin- ning system with which they can re- utilize their own production waste. Very much in line with the circular economy. The VacuFil recycles this waste. The VarioFil then spins the processedmaterial. Whereby the Va- cuFil stands on its own, of course, and can also be combined with a granu- lation process and other further pro- cessing procedures. Equally, starting materials other than spinning waste can be processed as well – such as bottle waste, trays, fi lms, etc. On the one hand, these of course have completely different properties and, on the other hand, the requirements of the subsequent recycled material also vary depending on the end use. To ensure the VacuFil is able to ful fi ll such changing recycling tasks in a re- liable and reproducible manner, the fl exible controlling of the intrinsic viscosity was the top priority during development. Where do you acquire your know- how? Processing virgin material into fi lms and fi laments and recycling polyester are actually two complete- ly different processes. Dr Schäfer: Of course, these are two completely different processes, but we view the necessary conversion into recycled material from perspec- tive of the end product. The desired properties of the end product de- termine the requisite quality of the starting material and hence also the requirements for the recycled mate- rials and their production. We come full circle. Hence, we know precisely what is important when recycling PET to ensure that further processors are able to use it to create high-qual- ity products. In theory, that sounds very promis- ing. What does the performance look like in practice? Schmitz: Our trials have shown that – in the right con fi guration – our high- end extrusion and, above all, our fi ltration technologies are able to produce high-end rPET granulate for high-quality POY or FDY. Our system creates an intrinsic-viscosity build-up of up to 0.15 dl/g and homogeneity fl uctuations of just ± 0.01 dl/g. We have achieved outstanding results in our tests. In part, the recycled materials from our VacuFil systems even offer superior spinning proper- ties compared to the virgin material used in the tests – particularly with regards to spinning breaks and lint formation. We offer our test system to customers and other interested parties for speci fi c material and pro- cess tests. These are surprisingly positive re- sults, considering you normally have to accept compromises when using recycled materials. How have you achieved this? What is so special about the VacuFil process? Schmitz: Fundamentally, we use liq- uid-state polycondensation, which cleans more effectively than solid- state polycondensation processes. But the truly special feature with the VacuFil is, above all, our Visco+ com- ponent. With this, we have devel- oped a unique vacuum fi lter system for viscosity build-up and viscosity homogenization. We currently have a patent pending here. Add to this the interaction with high-end extru- sion, large-area fi ltration and the ex- cellent degasi fi cation technology. Dr Schäfer: The right con fi guration of these units is absolutely decisive. We are proud that we have succeed- ed here, drawing on our many years of extrusion and fi ltration expertise. Mr Schmitz, you mentioned that the VacuFil is compatible with vari- ous further processing procedures. What possibilities do manufacturers actually have? Schmitz: You can combine the Vacu- Fil with various pelleting units. How- ever, you can also feed the recycled melt from the VacuFil directly into the further processing systems, re- gardless of whether these are spin- ning systems, fi lm production units or other manufacturing processes. There are many possible options. BB Engineering also offers several op- tional add-ons for the VacuFil. For example, our 3DD mixing system, which enables the recycled material to be returned to the virgin polymer fl ow in a polycondensation system. This mixing system can also be used to add additives, masterbatches and similar to the rPET melt. Overall, the VacuFil is extremely modular and fl exible. A really exciting system. We wish you continued success and thank you for talking to us! BB Engineering GmbH Leverkuser Str. 65 42897 Remscheid, Germany www.bbeng.de The VacuFil test system at the company HQ in Remscheid is available for customers and interested parties for material and process testing