They can be added to engineering polymers including polyamides, polyesters, and thermoplastic urethanes. The masterbatches are based on proprietary phosphorous compounds instead of halogens and achieve flame-retardant properties through intumescence. When exposed to fire, the material foams and cross-links, forming a stable char at the surface. This protective layer provides thermal insulation, reduces oxygen access, prevents dripping of molten polymer, and cuts smoke density and toxic emissions. CESA-flam XP 8451/XP 8454 has a limited oxygen index in the 28 to 30 range, while XP 8429 and XP 8486 flame ratings meet UL94V-0 standards.
