PHOTOFADING OF DISPERSE AND VAT DYES IN POLYESTER AND POLYESTER/COTTON BLENDS WHEN SUBJECTED TO WEARING AGENTS

摘要

Photofading of disperse and vat dyes on different substrates was found to be dependent on time of exposure and the conditions of fading, such as presence or absence of water and alkaline or acidic perspiration. Perspiration clearly enhances the extent of photofading. Every single disperse and vat dye exhibited varied extent of photofading on polyester/cotton blends, which further showed dependence on the composition of the blend. The response of individual dyes to photofading was further influenced by the presence of other dyes, and hence the behaviour of the dyes to photofading in presence of each other becomes more complex in nature. Finishing enhances the photofading of the dyes.In general, acid perspiration has the maximum deteriorating effect on the photostabilty of the dyeings. In other words, a number of factors such as nature of the substrate, chemical class of the dye and the structure of the dye in addition to wearing agents and the types of finishes govern the overall behaviour of the dyeings with respect to photofading. Thus in order to meet the consumer's expectation in terms of quality standards all the above mentioned findings need to be given due considerations while processing the fabric.