24 Apr 2025

Celebrating 50 years of flame retardants: Exolit^™ AP leads the way to a more sustainable future

2025 marks the 50th anniversary of Clariant's Exolit AP flame retardants, showcasing half a century of protecting lives and property worldwide
The successful launch of melamine-free Exolit AP in 2024 represents a breakthrough as an SVHC-free innovation while maintaining superior fire resistance performance
Clariant is actively seeking development partners to collaborate on next-generation flame retardant solutions

MUTTENZ, April 24, 2025 - In 2025, Clariant is proud to celebrate a significant milestone: 50 years of Exolit AP flame retardants protecting lives and property around the world. Based on advanced ammonium polyphosphate (APP) technology, these pioneering flame retardants have become the industry benchmark in a wide range of applications, including intumescent coatings, fire barrier sealing systems, thermoset composites for e-mobility battery housings and coatings, rigid polyisocyanurate (PIR) insulation foams and more. As Clariant marks this golden anniversary, it is not just celebrating past achievements but actively shaping the future of fire protection.

A legacy of innovation

Since producing the first batch of Exolit AP at the Knapsack site in Germany in 1975, the Exolit AP product line has pioneered flame retardant technology. What began as a groundbreaking solution has evolved into a comprehensive portfolio that sets industry standards for performance and reliability. The recent launch of a melamine-free Exolit AP grade demonstrates how this spirit of innovation continues today.

Innovation for today and tomorrow

The successful launch of melamine-free Exolit AP marks a significant step forward in more sustainable flame retardant technology. This SVHC-free solution, without the addition of melamine, demonstrates Clariant’s commitment to meeting stringent safety and sustainability demands while maintaining superior fire resistance across multiple Passive Fire Protection (PFP) solutions such as fire stop systems and intumescent coatings, as well as flame-retardant applications like insulation panels. This development responds to the rising demand from health- and sustainability-conscious consumers and brands, including those who are actively seeking safer alternatives to products containing substances of concern. Similar to the growing adoption of PFAS-free alternatives across various markets, there is a clear shift in purchasing behavior towards safer solutions in PFP.

Exolit AP 435: same trusted performance, now even better for tomorrow

Building on this momentum, Clariant is excited to preview the next evolution in the journey towards melamine-free fire protection: an enhanced version of the trusted Exolit AP 435.

This evolution maintains the exceptional performance characteristics in water-based formulations that have made Exolit AP 435 the industry benchmark for shelf-life stability, while incorporating forward-thinking improvements to meet future regulatory requirements, all without compromising on fire protection performance.

The power of partnership

Clariant’s success story is built on strong partnerships with customers, many spanning generations. In the continued development of next-generation solutions, Clariant is engaging with forward-thinking companies interested in shaping the future of sustainable flame retardants. This collaborative approach ensures that innovations align perfectly with market needs while maintaining high-performance standards.

To show that significant innovations are best achieved through partnership, Clariant is actively seeking development partners who share the vision for more sustainable fire protection and want to be at the forefront of industry innovation. This collaborative approach allows helps to refine solutions while ensuring they meet real-world performance demands.

Milestones that matter

Clariant’s 50-year journey has been marked by significant breakthroughs:

1975: Introducing Exolit AP 422 flame retardant
1983: Launching Exolit AP 462, encapsulated ammonium polyphosphate (APP)
1990s: Development of specialized solutions for intumescent coatings
2000s: Strategic expansion of intumescent coatings market
2015: Launching Exolit AP 435, setting new standards in viscosity control
2024: Introduction of the very first melamine-free Exolit AP
2025: Continuing development of next-generation solutions

"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.

Today, this legacy of innovation continues. “The launch of melamine-free Exolit AP represents more than just a new product,” explained Adrian Beard, Global Industry Market Manager Flame Retardants. “It embodies our commitment to combining five decades of expertise with tomorrow's sustainability demands.”

The road ahead

As Clariant looks to the next 50 years, its commitment to innovation remains stronger than ever. The success of the very first melamine-free Exolit AP grade and the evolution of Exolit AP 435 demonstrate how the company can meet evolving industry needs while maintaining the high-performance standards that have defined Clariant’s products for half a century.

Stefan Brejc, Global Vice President Segment Coatings & Adhesives proudly stated, “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.”

Watch the video to learn more: Coatings and Adhesives Webinar Series.

Note to the editors:

Clariant celebrates a significant milestone in 2025: 30 years since its foundation and 50 years of Exolit AP. These anniversaries are closely linked, as Exolit AP was originally developed by Hoechst AG, whose specialty chemicals business was acquired by Clariant in 1997. This acquisition not only expanded Clariant's global presence but also brought Hoechst's innovative portfolio into the Clariant family.

It's important to note that while Clariant was officially founded in 1995, the legacy of Exolit AP dates back to Hoechst AG, making 2025 a double celebration of innovation and heritage for both Clariant and its renowned flame retardant additive. This context highlights the shared heritage and provides clarity for readers.

For more details on Clariant’s history and milestones, visit our history page: Clariant at a Glance – History.

Learn more about Clariant’s Intumescent coatings here.

Exolit^™ IS A TRADEMARK OF CLARIANT.

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Notes for editors

www.clariant.com

Clariant is a focused specialty chemical company led by the overarching purpose of “Greater chemistry – between people and planet.” By connecting customer focus, innovation, and people, the company creates solutions to foster sustainability in different industries. On 31 December 2024, Clariant totaled a staff number of 10 465 and recorded sales of CHF 4.152 billion in the fiscal year for its continuing businesses. Since January 2023, the Group conducts its business through the three Business Units Care Chemicals, Catalysts, and Adsorbents & Additives. Clariant is based in Switzerland.

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Related images

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

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