Indigo dyeing of cotton yarn chain - involves adding wetting agent to at least first of several dye immersion troughs

摘要

A process is for indigo dyeing a cotton yarn chain and entails using a wetting agent, which is added to the dyestuff of at least the first dye immersion trough. The dye bath of the trough with the wetting agent is circulated individually with a subsequent addition of dye and/or chemicals in accordance with the level and material exchange. The ratio of wetting agent to the dyestuff in the trough is set at the minimum amount of dye required for dyeing fast the material. Pref. wetting agent is also added to the second immersion trough - the amount is pref. relatively smaller than in the first trough. Less wetting agent is added to the successive troughs (in the direction of the chain transport) from trough-to-trough either singly or in groups of troughs. ADVANTAGE - The process ensures that the dye layers are applied evenly and reproducibly thinly in the successive troughs and can be oxidised virtually completely.