Clariant celebrates 50 years of Exolit fire retardants

The company said the Exolit AP range, first produced at the Knapsack site in Germany in 1975, has evolved into an industry benchmark for halogen-free flame retardant technologies. The products are used in intumescent coatings, fire barrier sealing systems, thermoset composites and insulation materials.
The anniversary comes as Clariant continues to expand its portfolio with more sustainable formulations. In 2024, the company introduced an SVHC-free grade designed to meet increasingly stringent health and environmental requirements while maintaining fire protection performance.

Building on this development, Clariant is also preparing an updated version of Exolit AP 435, aimed at improving regulatory compliance while preserving the shelf-life stability and performance characteristics that have made the product widely used in water-based systems.

“Through changing times and evolving industry needs, Exolit AP has remained at the forefront of innovation. From its origins in Hoechst AG to becoming a cornerstone of Clariant's portfolio in 1997, each decade has brought new challenges and achievements. The introduction of Exolit AP 462 in 1983 marked our first major breakthrough in encapsulated ammonium polyphosphate technology, setting new industry standards for performance and reliability,” said Achim Hennemann, head of market segment passive fire protection.

Adrian Beard, global industry market manager flame retardants, added: “The launch of new SVHC-free Exolit AP represents more than just a new product. It embodies our commitment to combining five decades of expertise with tomorrow's sustainability demands.”

Among the milestones highlighted by Clariant were the launch of Exolit AP 422 in 1975, the introduction of encapsulated Exolit AP 462 in 1983, expansion into intumescent coatings during the 1990s and the release of Exolit AP 435 in 2015.

The company introduced its latest SVHC-free products in 2024 and said development work on next-generation solutions is continuing.
Clariant is also seeking development partners for future flame-retardant technologies.

“The same pioneering spirit that drove our first innovations in 1975 still drives us today. As we celebrate this golden anniversary, we're not just looking back at 50 years of achievement, we're building on this foundation to create the next generation of more sustainable flame retardants,” said Stefan Brejc, global vice president segment coatings & adhesives.

Exolit AP was originally developed by Hoechst AG. The product line became part of Clariant's portfolio following the Swiss specialty chemicals company's acquisition of Hoechst's specialty chemicals business in 1997.

Photo: Clariant’s intumescent coatings foam and expand when exposed to high heat, forming an insulating char that protects the underlying material. © Clariant

Clariant