To address the tightening outlook for thermal treatment of plastics, KraussMaffei, together with BASF, Rampf and Remondis, is industrializing a continuous chemical recycling route for polyurethane insulation foams from end-of-life refrigerators. The approach, based on depolymerization via a modified glycolysis run in a co-rotating twin-screw extruder, is designed to handle heavily contaminated PUR regrind, including residues of other plastics and metals at levels up to 30 percent. In the purity glycoLine PU process, regrind from Remondis' refrigerator recycling operations is metered with depolymerization agents and additives into a ZE BluePower extruder, where polymer chains are broken down within minutes to form an intermediate. Foreign substances are then removed directly in-line through filtration adapted by KraussMaffei to meet polyol market requirements. The resulting recycled polyols can be used at BASF as components in rigid foam systems with recycled content. The partners indicate that the process is already economically attractive. At K 2025, KraussMaffei plans to demonstrate live processing of the PU system with recyclate content into foamed beverage insulators, and will also introduce a RimStar metering machine prepared for digitalization and future autonomous operation.
Continuous glycolysis process for contaminated PU foam
In contrast to widely used batch methods, the extrusion-based approach enables continuous depolymerization of PU regrind. Within the purity glycoLine PU setup, the co-rotating twin-screw ZE BluePower provides intensive mixing of the PUR feed with depolymerization agents and selected additives. This configuration allows efficient processing of material streams with impurity levels up to 30 percent, including other plastics and metal particles.
The extrusion step generates an intermediate that can be cleaned in-line. KraussMaffei reports that it has tailored the downstream filtration to polyol quality requirements, validated in tests at its Innovation Center. According to the partners, the recycled polyols can be incorporated by BASF into PU rigid foam systems containing recycled content, supporting circular use of insulation foams from old refrigerators.
Sustainable cycle thanks to purity gycoLine PU: The PU components of items such as refrigerators are converted into polyol with recycled content (rPolyol) at the end of their service life using an extruder in a continuous chemical process.
Metering technology prepared for digital and autonomous operation
The Reaction Process Machinery team is introducing a RimStar series metering machine configured for digitalization and future autonomous operation. The new features aim to simplify machine and process control, including for less experienced users. Over time, selected operator tasks could be transferred to automated functions.
Digital analysis tools are integrated, notably dataXplorer, which records and evaluates all relevant process data. The results are intended to form the basis for automatic adjustments during production in subsequent development stages.
KraussMaffei at K 2025: Hall 15, Booth C24.
