A: One bath one step method: dyeing in alkaline bath, that is, fixing at the same time of dyeing.
This method has the advantages of simple process, short dyeing time and convenient operation.
However, due to the simultaneous adsorption and fixation, the dye can not be diffused after fixation, so the levelness and dye permeability are poor.
When dyeing in alkaline condition, the dyestuff stability of dyeing bath is more than that of hydrolysis.
B: One bath two-step method: dyeing in a neutral bath, when the dye dyeing is close to equilibrium, add alkali in the dyeing bath, adjust the pH value to the specified pH value of fixation, (generally 11).
At this time, the dye and fiber achieve covalent combination to achieve the purpose of fixation. One bath two-step process is a reasonable dyeing method in reactive dye dip dyeing.
It can not only obtain higher dye uptake and fixation rate. This method is often used in cotton knitted fabric dyeing because of its good leveling effect.