Bleachability and Dyeing Properties of Biopretreated and Conventionally Scoured Cotton Fabrics

Enzymatic (cellulase, pectinase, xylanase) and simple buffer treatments in the presence of a nonionic surfactant improve water wettability of fabrics to a level equal to conven tional alkaline scouring. Caustic scoured fabric is significantly lighter and less colored than all the biopretreated samples. Application of a hydrogen peroxide bleaching subse quent to the biopretreatment is beneficial because it reduces the great color differences between conventionally scoured and biopretreated samples. Bleachability of the pretreated fabrics is better than that of the conventionally scoured sample. Biopretreated fabrics can be dyed with a reactive dye subsequent to the enzymatic treatment without further oxidative bleaching. At higher dye concentrations ( i.e., 1 or 2%), there is no perceptible color difference between the biopretreated and alkaline scoured fabrics in the dyed state. In pale and medium dyeings, however, the color difference is great and perceptible. Bleaching applied subsequent to bioscouring significantly decreases the color difference between the dyed samples pretreated in different ways. None of the pretreatments causes uneven dyeing. Wash fastness of the dyed samples is excellent and unrelated to the pretreatment method.