Flame Retardant Textile Back-Coatings. Part 1: Antimony-Halogen System Interactions and the Effect of Replacement by Phosphorus-Containing Agents

A series of back-coated cotton fabrics comprising varying molar ratios of chlorine, bromine and antimony has been studied using a simulated match ignition test, LOI and thermal analysis (TGA and DTA). Results show that the presence of chlorine alone and in combination with bro mine increases LOI and carbonaceous char values at optimum halogen :anti mony molar ratios of 2.5-3.6:1 and bromine:chlorine molar ratios within the range 0.31-0.42. Only back-coated samples containing bromine pass the simu lated match test although at Br:Sb molar ratios above 4:1, LOI and char residual values decrease. It is evident that condensed and vapour phase flame retardant mechanisms are operating with efficiencies determined by halogen : Sb and Br/Cl molar ratios. Partial and whole replacement of halogen and antimony by phosphorus-containing and other flame retardants in the back-coating formulation that do not function in the vapour phase may be used to pass the simulated match test.