Several treatment methods after oxygen bleaching of cotton knitted fabrics

After the oxygen bleaching of the cotton knitted fabric, if it is not fully washed, what will be the impact on the dyeing?

If the washing is not clean, the residual hydrogen peroxide on the fabric will be carried into the dye bath, which will oxidize and decompose the reactive groups of the reactive dyes:

Light color

2. Spots

3. Hue changes, etc.

How can we effectively remove residual hydrogen peroxide from fabrics on knitted fabrics?

In the dyeing production, the residual oxygen in the dyeing bath can be washed by the following methods.

High-temperature washing method

Specific process:

Oxygen bleaching after cooling to 80 degrees drainage - water injection heated to 80 degrees, insulation for 10 minutes - drainage - water injection. Add acid and run at 40 degrees for 10 minutes - Drainage - Water wash once or twice, each for 10 minutes. Then start the staining.

2. Reducing agent method

Ten minutes prior to the end of the oxygen bleaching, 0.5 g/l of the infusible powder was added to eliminate residual oxygen.

3. Biological enzyme removal method

Hydrogen peroxide is removed by the decomposition of hydrogen peroxide using a hydrogen peroxide enzyme.

Process: After oxygen bleaching, cool down to 80 degrees Drainage - water injection - Neutralize with acid to pH 7, add oxygen scavenging enzyme 0.07g/l, treat at room temperature for 10-15 minutes.

Determination of residual hydrogen peroxide:

Hydrogen peroxide concentration test paper

Potassium permanganate or heavy complex acid titration.

Comparing

Traditional high-temperature washing requires the consumption of large amounts of water, electricity, and gas, which increases the water treatment and cost burden of the dyeing plant. In the current situation of tight environmental pressure, it should not be used.

2. Reducing agent method, it is difficult to grasp whether the residual oxygen is removed, such as excess reducing agent, it will also affect the dyeing.

3. Bioenzymatic method is the ideal removal method at present.