Customized Recycled PET through BBE-Technology

The BB Engineering VacuFil process enables the re-utilization of PET – or polyester*) – waste into high-end textile filament and fiber products in defined qualities.

Sustainable handling of natural resources is a global task, the Germany-based company BB Engineering (BBE) underlines. This would relate in particular to the further development of the circular economy for post-consumer or post-production waste. For this reason, the recyclability of PET (polyethylene terephthalate) products made by the industry is attributed special significance. Modern resource-friendly packaging would not be conceivable without PET and commodities generally made from chemicals. As a raw material that is – along with polyolefins and polyamide – such a dominant raw material, that polyester must be also recycled.

The recycling of polyester materials and the possibilities for converting the waste into new high-end products within the polyester filaments, fibers and nonwovens market are state-of-the-art. Across the globe, consumers in the markets are demanding sustainable products and the careful utilization of resources – increasingly in the textile sector as well. Leading fashion companies, sports apparel and furniture manufacturers and the automobile industry are focusing on sustainable products and products made from recycled materials to a greater extent. Today, they are already telling suppliers of filaments, fibers and nonwovens that they soon will be switching from exclusively virgin polyester to recycled polyester – in some cases up to 100 percent – for the manufacture of their textile products. Consumers’ social awareness has been the trigger for this development.

The original idea – namely to manufacture sub-premium goods using recycled polyester raw material, for example for use in insulating materials – is short-sighted from today’s perspective. Recycled polyester has long been prevalent within the high-end textile segment. Viewing polyester as a valuable resource rather than as waste is an important and proper development.

VacuFil recycling process: reproducible quality
Fibers and filaments made from recycled bottle flake material require corresponding single-variety collection or pre-sorting of the bottle material being recycled and comprehensive cleaning before they are shredded into polyester flakes. It is then possible to spin these flakes directly into POY (Partially Oriented Yarn) filaments (DTY [Drawn Textured Yarn] in the downstream process), staple fibers, nonwovens and BCF (Bulked Continuous Filament) endless filaments. Today, the technology is so refined that the products achieve a quality standard that corresponds to virgin material in many applications.

BBE – a joint venture between Brückner Group GmbH (a world market leader for machines for the polyester foil industry) and Oerlikon Textile GmbH & Co. KG (a world market leader for systems for the manmade fiber industry) – is a pioneer in the development of processes for using recycled materials. This applies particularly to polyester flakes, which are converted into contemporary, market-appropriate products for filaments, fibers and nonwovens for manmade fiber industry consumers.

“Our decades of competence kicked in while we were developing the VacuFil. What Oerlikon Barmag brings to the table as a technological leader in the field of filament yarn spinning systems, BBE complements with considerable know-how in the area of extrusion and filtration and systems construction and engineering”, Dr. Klaus Schäfer, CEO of BBE, was quoted. As a result of its association with the Brückner and Oerlikon Textile groups, BBE was aware of the requirements of the further-processing industry in terms of granulate and melt made from recycled polyester.

When it comes to the downstream processes with the VarioFil spinning system – the basis for spinning high-end manmade POY and FDY fiber filaments for textile and industrial applications that have been tried-and-tested for decades now – BBE is already an established manufacturer of compact and flexible systems for the manmade fiber industry. VarioFil R spinning systems have been used for converting PET re-granulates and – directly – PET flakes into POY/DTY for both textile and carpet applications. And spin-dyed products made from PET recycled granulates are also being produced using VarioFil systems.

However, there are also many cases in which the material quality and/or property achieved does not comply with the market requirements. For numerous textile applications, parameters such as viscosity and homogeneity are crucial and must be subject to virtually no fluctuations. In other words, to enable recycled polyester to be used here in the first place necessitates its pre-treatment. And this is carried out by the VacuFil recycling process, a BB Engineering GmbH development. The VacuFil technique enables the manufacture of extremely homogeneous, viscosity-stable rPET melt and hence a precisely definable and reproducible raw material for downstream processes (for example a spinning plant). As a manufacturer of components and systems for producing

Matthias Schmitz, VacuFil Product Manager, and Dr. Klaus Schäfer, Managing Director (Photos: BBE)

manmade fibers, BB Engineering (BBE) is familiar with the dire impact that even the smallest viscosity deviation has on the spinning plant process. With the VacuFil process, the company has succeeded, depending on the intended end application, in aligning the melt with the process in a targeted manner. Macro- and microscopic melt homogeneity is achieved through homogenization drying, controlled plasticizing, gentle filtration and controlled vacuum degassing.

In the downstream processes, the melt can either be first granulated or fed directly into the end product’s manufacturing process. Recycled polyester, produced using the BBE VacuFil technique, can even be used for more challenging downstream processes, including the manufacture of FDY (Fully Drawn Yarn) filaments, for example. Here the material is subjected to extreme loads throughout the entire manufacturing process. In the FDY single-stage process, the filaments are drawn and taken up at speeds of up to 4,500 meters per minute.

Tests for global customers
VacuFil premiered at the ITMA 2019 in Barcelona. Since then, numerous tests have been conducted on the pilot system at the Remscheid site using authentic waste material supplied by various customers. Various target viscosities and starting materials are not a problem for the VacuFil thanks to the innovative key component, the Visco+ vacuum filter. A reactor is not required. The VacuFil unites gentle large-scale filtration and swift intrinsic viscosity build-up for consistently outstanding melt quality. The attached vacuum unit is automatically regulated and “removes volatile contamination, ensures a controlled IV increase and additionally achieves an ideal melt homogeneity, which is vital for the downstream spinning performance,” the company assures. Comprising an inline viscosity measuring unit connected to the vacuum system, the IV can be continuously and reliably adjusted. Hence, producers can generate the specific kind of recycled polyester they require for their application. “The excellent degasification performance additionally relieves energy-intensive pre-drying.” With their modular structure and a performance spectrum of between 300 and 3,000 kilograms/hour, “VacuFil systems open up various possibilities for processing polyester waste”. The entire recycling process is controlled and monitored by Oerlikon Barmag’s GUIDE system, guaranteeing the accustomed reliability. “With an optional 3DD mixer, the market-proven mixing technology manufactured by BBE, producers can not only add additives to the melt, but they can also easily change rPET ratios in the main melt from between five and 50 percent stream in order to comply with legal standards.”

Customer requirements can be optimally catered for with various system configurations. “The close collaboration between the future operators of the system and our experts ensures that projects are successful,” Matthias Schmitz, VacuFil Product Manager, is cited. With BBE’s process visualization system, customers always would have a close eye on the broad operating window and the optimum operating point. The company’s customer-centric approach is also available throughout the coronavirus pandemic. BBE offers digital video conferencing to continue providing access to their technology for their global customers.

www.bbeng.de/recycling-technology.html

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*) Editor’s note: Polyethylene terephthalate (PET) is actually polyester. When this type of plastic is used for bottles, containers and other applications, it is called PET. In the context of textile applications, PET is referred to by its common name, polyester.

(Published in GLOBAL RECYCLING Magazine 1/2021, Page 41, advertorial, Photo: BBE)