Cyanamide-Based Durable Flame-Retardant Finish for Cotton

Abstract

Results of recent work on the cyanamide-phosphoric acid flame retardant for cellu losic fabrics are reported. It is shown that this flame-retardant system can be applied to fabric in various ways to impart flame retardancy to cellulosic fabrics without seriously affecting the hand of the fabric, but that precautions are necessary to counter act a very rapid exothermic reaction which occurs during the drying and curing of the treated fabric. It is shown that the flame retardancy obtained with the cyanamide- phosphoric acid system is durable to laundering, the degree of durability depending on the hardness of the wash water. The results show that exceptionally good durability to home laundering is obtained when washing is done in soft water, softened water, or with the use of water softeners (sequestrants) if laundering is carried out in hard water. Methods are described for restoring flame retardancy of treated fabric which has been laundered to failure. The cyanamide-phosphoric acid flame retardant is also shown to be durable to commercial laundering and drycleaning and that this flame- retardant finish also imparts wash-wear properties, shrinkage control, and rot resistance to cellulosic fabrics. It is indicated that this system has a deleterious effect on the shade of some dyes, that selection of dyes to use with this system is a problem, but one which is at least technically soluble. Experiments carried out to elucidate the chemistry of the reaction between cyanamide and phosphoric acid with cellulose are reported.