ATO-free flame retardants for high-voltage E-mobility applications by Clariant
Last update on Jun 12, 2026
Formulators developing flame-retardant PBT compounds for e-mobility applications can now evaluate two new Exolit OP grades from Clariant, both presented at K 2025. The grades are positioned for higher-voltage electrical and electronic systems, where electrical insulation performance and long-term stability are primary selection criteria.
Clariant has also completed a CHF 100 million investment at its Daya Bay facility, with a second production line reported operational in November. The company links the added capacity to demand for flame-retardant solutions across the Asia Pacific region and the e-mobility segment.
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Eliminating PTFE requirements simplifies formulation design
According to Clariant, Exolit OP 1242 (TP) is designed for hydrolysis stability, while Exolit OP 1266 (TP) is reported to maintain a comparative tracking index (CTI) of 600 V after extended storage. The supplier states that both grades meet UL 94 vertical V-0 down to a sample thickness of 0.4 mm at dosing levels of 15–20%. Clariant frames these attributes as relevant for systems rated at 800 V and above, where insulation and stability under sustained conditions become limiting factors.
You can review the Exolit grades data and compare them directly in the Master Catalog of Additives.
Both grades are halogen-free. Clariant positions them as alternatives to systems based on antimony trioxide (ATO), citing antimony price movement and supply variability in recent years, and notes the grades do not require fluorinated polymers such as PTFE. Formulators evaluating these grades will weigh that positioning against their own application constraints, OEM requirements, and qualification scope.
Separately, Clariant has expanded its Exolit AP portfolio with Exolit AP 422 A, a halogen-free ammonium polyphosphate flame retardant for insulation materials, composites, and intumescent coatings. Melamine is classified as a Substance of Very High Concern (SVHC) under EU REACH; according to Clariant, Exolit AP 422 A contains less than 0.1% melamine and is therefore SVHC-free under Article 31 of the REACH Regulation.
In polyurethane foam, the supplier reports the grade can replace TCPP (tris(chloropropyl) phosphate) and TEP (triethyl phosphate) without the plasticizing effects associated with those phosphates, and cites improved powder flowability for production handling.
Formulators working on flame-retardant compare the grades by performance attribute and regulatory status in the Master Catalog of Additives.