Exterol is a liquid polyester polyol modified with a very active non-halogen reactive flame retardant group, which guarantees: halogen free condition, very high flame retardant activity (3 times more than phosphate), no migration effect, very high mechanical properties of final product, no decay of flame retardant properties OVER time.
These positive effects are obtained because Exterol is a flame retardant, which is also a polyester polyol that reacts with isocyanate, like any other polyols, and therefore doesn’t migrate outside of the foam and it’s not behaving as a passive additive in the formulation