Flame-Retardancy Transfer from FR Cotton Fabric to Cotton/Polyester Blends

Flame-retardancy transfer from cotton fabrics flame-retarded (FR) with phosphorus-containing compounds to adjacent, untreated cotton/polyester blend fabrics was observed during burning. Reduced flammability was found for blends containing 35% or less polyester; this was indicated by the fact that the char weight for burning FR cotton and untreated blend was higher than that for separate burning; however, when the level of polyester was above 35%, there was essentially no evidence of reduced flammability. Transfer of phosphorus from FR to blend fabric was detected by analysis of chars from blends of high cotton content. Preferential pickup of flame retardant by the cotton portion of the blend is indicated.