Soufflé and Foam Insulation – What do they have in common?
Insights from the PLANETS Flame Retardant Workshop (19-20.03.2025)
In the project PLANETS, the Flame Retardants Case Study focuses on the development of safer and more sustainable alternatives for flame retardants used in thermoplastics made from polystyrene and thermoset foams derived from polyurethane.
To produce expanded polystyrene (EPS) materials, solid beads of polystyrene are used. These beads contain not only polystyrene but also additives required for the final product, such as dyes (coloring agents), nucleating agents, and flame retardants. During EPS production, the solid beads undergo a significant increase in volume due to the effect of a blowing agent and gentle heating. In contrast, polyurethane (PU) foam insulation does not require a heating process. PU foams form spontaneously when monomers, which already contain all necessary additives, are mixed together. This chemical process can be likened to baking a soufflé—only instead of eggs, sugar, and flour, a chemist “chef” uses various chemical ingredients. Just as a soufflé recipe must be carefully followed to achieve optimal results, the successful creation of polymeric foams relies on precise ingredient ratios, exact formulations and well-chosen process parameters. Alterations to an optimized recipe—for instance, changing the flame retardant—may adversely affect the final quality and performance of the foam. But don’t panic, unlike a soufflé, our insulating foams do not collapse.
For this reason, PLANETS chemists met with engineers and SSbD experts on 19-20 March 2025 during a two-day workshop held at Steinbacher Dämmstoffe, in their headquarters in Erpfendorf in Tyrol (Austria). The timing of this workshop coincided with the upcoming launch of an important task within the flame retardant case study: Material and Foam Development. This task, led by Fraunhofer ICT, will involve optimizing formulations for EPS beads as well as PU mixtures, later tested by Steinbacher Dämmstoffe in large scale productions.
On the first day, Benedikt Bitzer (Fraunhofer ICT) introduced partners to technical aspects and challenges associated with the foam production processes and discussed essential material property requirements. Additionally, partners responsible for flame retardant development provided updates on their technical progress. On the second day, Thomas Hennequin from TNO conducted a dedicated SSbD session to familiarise industrial partners with proposition for a PLANETS SSbD workflow and collect their suggestions for improvements so it can best fit their innovation practices.
At first glance, applying SSbD criteria to select the safest and most sustainable flame retardant from a pool of alternatives, already in an early development phase, seems logical. But what if the chosen flame retardant adversely affects foam formation? Such a situation could potentially render a lengthy and expensive SSbD evaluation obsolete. Conversely, prioritizing technical performance alone carries risk, as the safety and sustainability of a new flame retardant could unintentionally become worse than current benchmark substances—a regrettable substitution scenario. PLANETS is fully aware of these pitfalls and proactively addresses them by placing functional performance at the core of its SSbD approach, ensuring the flame retardants developed are suitable along the entire value chain, from upstream chemical design to downstream application. Indeed, applying SSbD criteria as early as possible serves the best interests of innovators and companies alike, preventing costly setbacks and potential market failures.
When aiming for a safer planet, a common understanding of methodologies and evaluation criteria among stakeholders is crucial for success. This is exactly why PLANETS partners Fraunhofer ICT, TNO, BASF, PLUS, Budenheim, GreenChemicals, RINA, QSAR Lab, BNN and CEA gathered online and on-site at Steinbacher during sunny spring days in the Austrian alpine town of Erpfendorf.
