Process for the one-bath single-stage dyeing of mixtures of carrier-free dyeable polyester fibres and cellulose fibres

摘要

As was found in practical trials concerning the single-bath/ single-stage dyeing of cellulose fibres in a blend with standard PES fibres from an aqueous medium with combinations of reactive and disperse dyes, the conjoint use of the two different types of colorants by the HT process by exhaustion at neutral pH leads to a number of shortcomings: this pH is under HT conditions much too high for many disperse dyes and too low for the customary reactive dyes. In conjunction with further studies in this field it has been possible to demonstrate, in departure from the received wisdom, that many disperse dyes which are unstable at a neutral pH under HT conditions prove to be completely stable in a neutral liquor at the boil. Consequently, dye mixtures on the basis mentioned are usable specifically for the exhaust dyeing of blends with cellulose fibres of polyester fibres which are dyeable at the boil in the absence of carriers. Unexpectedly, the colour yield and reproducibility are better than under HT conditions.