CompoBack, produced by Brueggemann’s Italian subsidiary Auserpolimeri, is a new additive enabling polyolefin foams, HFFR compounds, as well as cable applications, to maintain their mechanical properties and dimensional stability at elevated temperatures. These materials exhibit thermoset-like behaviour without requiring an additional cross-linking step. At the same time, they remain fully melt-processable without additional measures. Unlike permanent cross-linking, this reversible stabilization mechanism ensures compatibility with conventional polyolefin recycling streams, enabling recovery, and reprocessing without loss of performance.
Credit: L. Brüggemann GmbH & Co.KG
Shrinkage of rectangular foam profiles after 24 h ageing at 100 °C.
CompoBack is supplied as colourless granules that are easy to process, and well dispersible. They are added to the base polymer during compounding or processing in an extruder. The mixing ratio can vary widely according to requirements.
Using CompoBack significantly improves e.g. expanded PE foams, making them more stable due to their enhanced temperature resistance. Comparative measurements on extruded square profiles made of physically foamed polyethylene show that thermal shrinkage is considerably lower. In laboratory tests, the profiles shrank by around 75% after 24 hours of storage at 100 °C without stabilization. However, when compounded with CompoBack and stored accordingly, the reduction was negligible, similar to that of PEX which is permanently cross-linked.
Other areas of application include extruded products, such as pipes with increased burst pressure, and profiles with improved dimensional stability. Because CompoBack improves surface quality, these compounds are also suitable for use in contaminated compounds containing recycling streams.
Paolo Arnaboldi, CEO of Auserpolimeri says: "The development of CompoBack is a major step toward environmental sustainability. First, it eliminates the need for the energy-intensive cross-linking of polyolefins using chemical or radiation techniques. On the other hand, CompoBack allows the development of new formulations bridging the gap between non-crosslinked and cross-linked compounds during use but still can be recycled. We are working on diversifying our CompoBack product range to provide products for a variety of applications."