Safe and Sustainable by Design, Scoping, and Simplified Assessment of Alternative Flame Retardants for Use in Polymer Insulation Foams followed by Intermediate Assessment

The European Green Deal emphasizes the importance of a SSbD strategy for chemicals and innovative materials. To implement this strategy effectively, the JRC, the WBCSD, and CEFIC have developed guidelines outlining criteria for SSbD and providing data-driven recommendations [1-3]. However, there have been few successful implementations of SSbD in R&D projects.
The PLANETS project aims to bridge this gap by promoting straightforward, effective, and cost-efficient SSbD strategies for materials and products from the molecular design and component formulation level up to recycling and end of life management, following a tiered assessment approach as a case study [4]. In PLANETS Simplified Assessment, we evaluated over 70 alternatives –s-triazine phosphonates, phosphoryl carbamates, organic phosphonates, polystyrene-organophosphorus-sulfur copolymers, polystyrene-DOPO copolymers in synergistic combination with thermal radical generators, and chemically optimized ammonium polyphosphates– to state-of-the-art halogenated flame retardants, including polyFR and TCPP, and as a reference HBCD. Social and economic assessments as well as absolute sustainability evaluations highlight the importance of considering trade-offs, especially due to critical raw materials. For instance, phosphorus and copper are critical raw materials and must be avoided ("Red Flag") according to the JRC SSbD Framework. However, in this case, phosphorus is essential for the technical functionality of highly effective halogen-free flame retardant suitable for foam applications able to substitute halogenated flame retardants, while copper serves as a reactive intermediate in some of the synthesis. This indicates challenges with “Red Flag” criteria in Simplified Assessments. In this case, the assessment will be continued further with Intermediate Assessments rather than a definitive stop for the flame retardants concerned.
In this work, we focused on Intermediate Assessments to identify alternatives to brominated polymeric flame retardants, starting with in-chemico assessments. This stage also included risk screenings of the selected alternatives, evaluating their hazard profiles and categorizing them based on performance, compatibility, cost, degradation products, and recyclability. Here, we emphasized safety and sustainability assessments throughout the innovation process, utilizing tools for SSbD assessment such as HARMLESS Decision Support System [5]. Additionally, we will develop guidance for future substitutions based on lessons learned from the entire assessment process, thus contributing to safer and more sustainable chemical practices.