The Potential for Volatile Phosphorus-containing Flame Retardants in Textile Back-coatings
A number of volatile phosphorus-containing flame retardant species has been identified as possible replacements for bromine-containing formulations used in textile back-coatings because of the need for vapor-phase activity. The selected retardants include tributyl phosphate (TBP), a monomeric cyclic phosphonate Antiblaze CU (Rhodia Specialites) and the oligomeric phosphate-phosphonate Fyrol 51 (Akzo). When combined with an intumescent char-forming pentaerythritol derivative (NH1197, Chemtura) and applied as a back-coating on to cotton and polypropylene substrates, significant improvements in overall flame retardancy are observed. One sample applied to cotton and comprising both TBP and intumescent passed the simulated match-ignition test, BS5852:1979:Part1 after a water soak at 40°C for 30 min. Determination of residual phosphorus within chars shows that there is significant volatile activity present in these formulations. Addition of volatile nitrogen as melamine also demonstrated improved flame retardancy in similar formulations.