Reductive Clearing after Disperse Dyeing
In order to achieve good color fastness on dyed textiles made of polyester, triacetate or their blends, the fabric must be reductively cleared after dyeing. Especially dark shades require thorough cleaning. The post-treatment removes excessive, non-fixed disperse dyestuff.
Conventional reductive clearing is carried out after an intermediate rinsing step in the alkaline pH range with hydrosulfite (sodium dithionite, Na2S2O4) and caustic soda (NaOH). After the reductive treatment, the goods must be thoroughly rinsed and neutralized. The salts resulting from the neutralization process further pollute the wastewater.
LEAN Process: Clearing in the Dyeing Liquor with PERISTAL MC liq.
An acidic clearing after disperse dyeing with PERISTAL MC liq. can be carried out in the cooling acid dyeing liquor. This means that no intermediate rinsing is necessary. The reducing agent is added at 70 to 80 °C and the dyed textile goods get reductively cleaned. If necessary, before adding PERISTAL MC liq. to the exhausted dyeing liquor the pH is adjusted to 3.5 to 4.5 with acetic acid.
Reductive clearing with PERISTAL MC liq. is a modern LEAN process. Compared to the conventional scouring process with hydrosulfite and caustic soda, the post-treatment with PERISTAL MC liq. offers a significant savings potential in water, energy, time and chemicals. Like our other LEAN processes, the LEAN process with PERISTAL MC liq. offers many advantages over traditional methods.
What does LEAN stand for?
Our streamlined LEAN processes are characterized by:
- Less time
- Economical processes
- Advanced chemistry
- New technologies
Advantages of PERISTAL MC liq.
We recommend PERISTAL MC liq., our liquid, highly effective reducing agent, for the use in the cooling acid dye bath. Reductive clearing with PERISTAL MC liq. after disperse dyeing offers the following advantages:
- easy handling, no dealing with powdery hydrosulfite needed
- automatic dosing possible since the product can be pumped
- no neutralization necessary after the reductive clearing
- significant savings in time, energy, water and chemicals
PERISTAL MC liq.
PERISTAL MC liq. is a highly effective reduction agent, which is applied for the clearing of dyeings with disperse dyes in the acidic pH range.