Sequestering products are necessary in any kind of preparation and dyeing process.
They consist of organic structures of different kinds and fulfil various functions, including the chelation of metal ions, i.e. both earth alkali ions (Ca and Mg) and transition ions (Fe – Cu – Mn), respectively responsible for:
- the build-up of incrustations / deposits in and on machinery
- Catalysis (creation of holes in the fibre) when working with strong oxidizing agents at a high temperature (bleaching)
Both of them causes changes in dyeing colour when the dyestuffs in use are particularly sensitive to metals.
In desizing baths, they prevent the dissolving of any glue particularly sensitive to electrolytes and hardness and thus extend the stability of the bath.
In dyeing baths, they act as chelating agents for any extra-bath structure that might alter the successful outcome of a dyeing bath (e.g. colour changes) or soil the machinery over time.
In some cases, they are of aid to the action of soaping agents.