Phosphorus-Nitrogen Flame Retardant via Copper Complex1

Copper salts were found to stabilize tetrakis (hydroxymethyl) phosphonium hydroxide (THPOH)-ammonium hydroxide solutions by formation of a complex thereby making it possible to apply THPOH to cotton fabric from a single bath without the use of gaseous ammonia.The effect of the concentration of copper salts, THPOH, and NH4OH on the stability of the solution was studied. Cotton fabric with good flame retardancy, strength retention, and hand was obtained by the use of conventional pad-cure techniques for applying the solutions. Cotton fabrics with approximately 17% add-ons retained their flame retardancy after 25 home launderings.