Fixation on Wool of Dyes Containing a Maleimide Group

The chemistry of dyes containing a maleimide group is discussed. The mechanism of dye fixation on wool in depths greater than 1. 5% has been investigated. In samples which were dyed at pH 3, 80°C, little covalent reaction took place. Extraction with solvents, used to determine the fixation ratio, caused changes in the dye, as well as some further reaction, giving rise to apparently high fixation ratios. Dyeings on nylon fibre confirmed that covalent reaction of dye with amino groups is possible, especially between pH4 and 5. The best results in terms of fixation and yield were obtained in a dyeing procedure where the pHwas raised slowly during the dyeing.