The Effect of pH on Flame-Retardant Finishes for Cotton Prepared from THPC and Various Bases

Abstract
Various bases are compared for the neutralization of tetrakis(hydroxymethyl)phosphonium chloride (THPC) in flame-retardant finishes for cotton. In the THPC/amide process, the use of sodium hydroxide as the base results in a progressive decrease in add-on with increasing pH, whereas with trimethylamine and other strongly basic tertiary amines, the add-on is constant up to pH 10. Trimethylamine also has a leveling effect in the THPOH/ammonia process, where the difference is more subtle. The fabric properties of cotton printcloth, sateen, and flannelette finished with the THPC Me3N amide formulation are independent of pH in the 5.0-9.0 range.