Recent advances in the use of zinc borates in flame retardancy of EVA

In this work, zinc berates are used as synergistic agents in EVA-ATH and EVA-Mg(OH)(2) flame-retardant (FR) formulations and as smoke suppressants. Moreover, the study by solid state NMR of the residues sampled at different times during cone calorimeter experiments of the formulations EVA-ATH and EVA-ATH/Zinc berate allows to propose a mechanism of action of the FR systems. it is demonstrated that the decomposition of Aluminium trihydroxide (ATH) to Al2O3 during the heating of the polymer results in an increase of the ignition time. Moreover the formation of Al2O3 in situ from ATH during the combustion of the polymer is the first event. Concurrently zinc berate degrades and it is proposed that a vitreous protective coating is created, which yields a more efficient char. (C) 1999 Elsevier Science Ltd. All rights reserved.