Case Study: Developing Safer and more
Sustainable Flame Retardants
WP4 – leader Fraunhofer ICT, main SSbD partner – TNO
What are flame retardants?
Flame retardants are chemicals designed to prevent materials from igniting or to slow down the burning process. The mechanism of action depends on the chemical structure of the flame retardant used. For example, some flame retardants, upon exposure to high heat (or flames), produce a layer of char that isolates the material underneath from further exposure to high temperatures. Other flame retardants release reactive chemicals when exposed to heat. These chemicals interrupt the chain reactions responsible for sustaining the fire.
Current State in the Chemical Industry
Flame retardants are often used for thermoplastics, such as polyethylene (PE) and polystyrene (PS). However, some of these flame retardants can pose health hazards and environmental issues. For example, hexabromocyclododecane (HBCD), a low molecular-weight brominated flame retardant used widely for thermoplastic foams is now classified as a persistent organic pollutant and has been banned in the EU. It was replaced by a polymeric alternative made from a brominated copolymer of butadiene and styrene (PolyFR) and by low molecular-weight aromatic brominated flame retardants (SR130 and FR720). The latter class of flame retardant is under particular regulatory focus since ECHA has identified general health and safety concerns for this subgroup of brominated flame retardants. Similarly, TCPP, a common flame retardant for thermoset foam materials like polyurethane (PU), has been identified as a potential carcinogen, highlighting the need for safer alternatives.
PLANETS’ Safe-and-Sustainable-by-Design Solution
The development of new flame retardants in PLANETS will follow the Safe-and-Sustainable-by-Design (SSbD) approach to ensure they avoid the health hazards and environmental impacts of HBCD and TCPP. Several classes of halogen-free flame retardants will be explored. Greenchemicals will focus together with Fraunhofer ICT on new flame retardant solutions for two different thermoplastic foam types made from expanded PS particles and extruded PE. Chemische Fabrik Budenheim will focus together with Fraunhofer ICT on new flame retardant solutions for thermoset foams made from PU. The most promising compounds will be tested by Steinbacher with the support of Fraunhofer ICT for applications in pipe insulation and molded or wire-cut insulation. BASF supports these developments with raw materials but in particular through their experience with the SSbD framework and toxicology assessments. The entire SSbD assessment team of PLANETS working on this case study is coordinated by TNO.
Flame Retardants Case Study – Progress & Next Steps
During the first 18 months of the PLANETS project, significant progress has been made towards the development and application of safer and more sustainable flame retardant alternatives. The SSbD Tier 1 assessment of the selected alternatives was completed in June 2025, followed by the first synthesis and characterisation of the alternatives and the development of initial foam recipes in April 2026. In May 2026, the first formulations containing PLANETS SSbD flame retardant alternatives were processed on Steinbacher’s industrial production line, marking an important step towards their practical application.
- M8 (June 2025): SSbD Tier 1 assessment of the flame retardant alternatives completed.
- M18 (April 2026): Initial flame retardant alternatives syntheses and characterization completed.
- M18 (April 2026): Initial foam recipes containing the flame retardant alternatives completed.
What’s coming next?
- M19 (May 2026): First formulations containing PLANETS SSbD flame retardant alternatives processed at Steinbacher’s industrial line.
- Q4/2026: Scale-up reactor for PLANETS SSbD flame retardant alternatives production at 50 kg-scale installed at Budenheim.
- End of 2026: Full SSbD Tier 2 assessments completed
Onsite WP4 meetings – Highlights of the (internal) collaboration within the Flame Retardants Case Study.