Antioxidant-induced yellowing of textiles

The yellowing of white and pastel coloured textiles and garments has been a problem for many years in the textile industry. In the last 15 years much evidence has been published which suggests that a large proportion of storage yellowing is attributable not to the yellowing of fibre substrate or textile finish but to the yellowing of phenolic antioxidants which migrate onto the textiles from polyethylene and polypropylene packaging. These mobile phenolic compounds interact with atmospheric pollutants, particularly oxides of nitrogen, to give yellow compounds. A brief outline of the problems of yellowing is given, together with the identification of the yellow substances produced by BHT (2,6-di-tert-butyl-4-methyl phenol) and possible mechanisms of their formation. Prophylactic measures that can be taken by the garment manufacturer and finisher to prevent or minimise yellowing are also discussed.