6PPD Replacement

Flexsys has narrowed its search for a tire-additive to replace 6PPD to two final candidate molecules, moving a safer alternative chemistry another step toward commercialisation.

The Ohio-based company, which announced the world’s first viable 6PPD alternative in November 2025, has now completed its screening program. Both shortlisted molecules sit outside the PPD chemical family, do not form a quinone transformation product during use, and have met the company’s safety, performance and environmental benchmarks.

Independent Aquatic Toxicity Testing

Flexsys has entered a Cooperative Research and Development Agreement with the U.S. Geological Survey, whose scientists will independently evaluate the two molecules’ effects on aquatic life — the concern that drove 6PPD’s phase-out push after the compound was linked to coho salmon die-offs.

The company said both candidates use substantially the same intermediate chemistry used to make 6PPD today, allowing the industry to keep existing manufacturing assets — a factor that supports faster adoption and lower total investment cost. Flexsys has pointed to late 2030 or early 2031 for commercial production, aligning with the 2035 date proposed to phase out 6PPD in tires.

A Tire Chemistry Shift Is Underway

The milestone signals that the shift away from 6PPD is no longer theoretical — it is a timing question. As tire makers prepare for reformulated compounds, the broader push toward safer, more sustainable tire materials continues to gain momentum across the supply chain.

Learn More About Sustainable Tire Materials

• Recovered Carbon Black Production
• Advanced Tire Pyrolysis Technology
• Feasibility Studies
• What Is Pyrolysis?

Partner With The KleanTeam for a More Sustainable Tire Supply Chain

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Tire chemistry is transforming, and recovered carbon black is part of the same shift. Klean Industries supplies rCB recovered from end-of-life tires, giving manufacturers a traceable, non-fossil carbon that complements reformulated, safer tire compounds.

Klean’s Key Advantages:

• ✅ 3 recovered carbon black (rCB) plants built in India over the past 2 years.
• ✅ Signed LOI to deliver five more rCB plants in India.
• ✅ Canadian government (DFAITC) recognized Klean for India cleantech / circular-economy trade.
• ✅ KBR added Klean’s proprietary TyreNova tire-pyrolysis technology to its IP portfolio.

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