One‐pass process for the continuous dyeing of polyester/unmercerised cotton blends with disperse/reactive dyes. Part 1: Investigation of limited colour depth of the dyed blend^†

In the continuous dyeing of polyester/cellulose blends, the trend over the last 20 years, towards shorter production runs and greater numbers of fashion shades, has led to the development of more productive processes, in particular, the use of a one‐pass pad–dry–thermofix process for the application of disperse and reactive dyes. However, there are limitations to such a one‐pass process, of which the most important is the limited colour depth that can be achieved on polyester/unmercerised cotton blends. The current study examines the reasons for this limitation, with a view to either modifying the dyeing process or designing superior dyes.