Lightfastness of Dyes on Wash-Wear Cotton

Abstract

A study of the accelerated lightfading of dyes caused by wash-wear agents on cotton fabric showed that substituent groups on the agent could change the effect unpredictably. Hydroxyl substituents, however, always gave a slower rate of fading. A previous mechanistic theory for the phenomenon is incomplete, since at least two separate actions occur. One requires the presence of residues from the agent at the time of exposure to light so that they may participate in the photochemical reaction. The other is a sensitization of the dye by the agent during treatment and does not require the presence of agent at the time of exposure.