Phosphonate Finishes for Fire-Retardant, Durable-Press Cotton

Continuing efforts to develop an economical flame-retardant, durable-press finish for 100% cotton fabric are described. A system based on the reaction product of guanidines, dimethyl phosphite, and formaldehyde (GDMPF), applied by a conventional pad-dry-curve process, gives fabrics with excellent flame retardance durable for over 50 home launderings. Dry crease recovery is in the range 220°-270°, depending on fabric construction and weight. A second system based on the in situ reaction of methyl phosphonic acid (MPA) and cyanamide, applied by a pad-dry-cure process at low pH, gives flame retardance durable for over 50 home launderings at add-ons of less than 10%. Fabrics have moderate crease recovery with excellent hand and strength retention. Phosphorus-nitrogen synergism and the role played by calcium in the deactivation of phosphonate finishes are also discussed.