Service Fading of Disperse Dyestuffs by Chemical Agents Other than the Oxides of Nitrogen

An extensive trial of acetate drapery fabrics dyed with new "gas-fast" blues has shown that active agents in the atmosphere, in addition to the oxides of nitrogen, can cause fading in service. This fading is oxidative in nature. It has been reproduced by an accelerated laboratory test in which fabrics have been exposed to concentrations of ozone somewhat higher than those ordinarily found in the atmosphere. This type of fading has been designated as "O-fading." All of the disperse blue dyes and some of the reds and yellows have been found to be subject to O-fading. However, the major problem is with the blues. Anthraquinone blues are bleached by O-fading without the reddening associated with gas fading. The O-fading can be inhibited by antioxidants such as the gas-fading inhibitor diphenyl ethylene diamine and the nongas-fading inhibitor p-octyl phenol. For optimum re sistance to both forms of atmospheric fading, acetate fabrics dyed with disperse blues, including gas-fast blues, should be processed with inhibitors. Laboratory tests have shown that O-fading takes place on Dacron 1 as well as on acetate and Arnel. 2 With Arnel and Dacron, a marked increase in resistance to O-fading is obtained on heat treatment. The penetration of the dye into the fiber is a factor in O-fading behavior, as evidenced by the increase in resistance to O-fading of Dacron fabrics dyed with carrier and by the effect of heat treatment. Optimum resistance to atmospheric fading of Arnel is obtained by the use of inhibitor plus heat treatment.