Flame retardant textile finishing: thermal analysis and dermal security

Many flame retardants (FRs) are brominated, and many of them are considered toxic, persistent and/or bio accumulative. A switch to non-halogenated alternatives for textile finishing is considered beneficial, but there is little knowledge about their environmental impact, their health risks during the production process and those in their final use. A conventional and an alternative FR (based on dialkyl phosphono carboxylic acid amine and ammonium sulfamate; urea and organophosphonate PO(OH)2-R-PO(OH)2, respectively) were applied to cotton fabrics that could be in touch with the skin in their final use. Burning and thermal behaviors and dermal toxicity when exposed to skin rubbing are evaluated. Fabrics treated show that both FR products act as FRs. The increase in the thermal stability of the tissue that causes an increase in the decomposition temperature is a relevant effect associated with the application of the conventional FR in the tissue, while the most important effect of the alternative FR lies in the increase of the residue at 600°C, associated with the generation of fewer volatiles, which has an impact on the intensity of combustion. The study of the dermal toxic potential of FR-treated cotton bed sheets showed that the two tested products do not penetrate into the skin when applied under the conditions used and were safe when in contact with the skin. Moreover, the alternative FR seems to be safer when in contact with the skin considering also its higher concentration in the textile.