Weathering Durability of Cotton Fabrics Treated with APO-THPC Flame Retardant

Abstract

The influence of APO/THPC mole ratio on durability of flame retarclancy, resin retention, and strength retention of treated cotton fabric was determined by means of natural and artificial weathering tests. In both types of weathering, the use of photo active dyes as a means of accelerating the tests was studied. APO/THPC mole ratios of 2 : 1-8; 1 gave greater durability of APO-THPC resin and flame retardancy than did the standard I : 1 ratio. Photoactive dyes accelerated outdoor weathering by as much as fivefold, without obscuring the effect of mole ratio on resin durability. Predyeing was more effective than afterdyeing in causing accelerated weathering. Increased APO/ THPC mole ratios also gave increased breaking strength retention during weathering of undyed fabric, but produced no improvement on dyed fabric. These effects also occurred in Weather-Ometer tests made in the presence and absence of photoactive dyes. The APO-Zn(BF4)2 flame-resistant, wash-wear finish showed improved weathering durability comparable to that obtained from high-mole ratios 'of APO/THPC. The chlorine content of APO-THPC-treated fabric was 81% to 96% of theory at all mole ratios of APO THPC, indicating at least two modes of copolymer formation. The rate at which phosphorus was lost from APO-THPC during weathering was generally equal to the rate of nitrogen loss, expressed in percentage losses/time. The APO-Zn(BF 4)2 finish lost phosphorus more rapidly than nitrogen, indicating a different mode of resin breakdown.