The process of clearing the excess disperse dye left on the surface of polyester/cotton fibre blends cannot be avoided for most colours, since this dye will later stain adjacent fabric. The process which is usually applied is the reduction clearing process using alkaline sodium hydrosulphite. This is however a very polluting process, due to the high values of CQO and conductivity obtained as a result of its application.
The reduction clearing on blends of CO/PE with sodium hydrosulphite is also a very long process and water intensive, due to the intermediate rinses necessary before dyeing the cotton component with reactive dyes.
Results showed that clearing with H2CLEAR is a less polluting, more sustainable, shorter process, and also has better fastness than the alternative reduction clear sequence.