Scouring, Bleaching and Enzyme Wash Recipe of Cotton Fabric

For more videos click to visit our YouTube Channel 

“Textile Bites - youtube”

Today we will discus about Scouring, Bleaching and Enzyme washing,  that is,   pretreatment of Cotton Fabric as done in Dyeing Factory.

The raw or greige cotton fabric contains a significant amount of impurities. In case of cotton fabric, it contains natural, added and accidental impurities. Natural impurities are impurities which the cotton fibre gathers during its growth. Added impurities are the wax and oil which are gathered during the process of spinning, knitting or weaving. Lastly, accidental impurities are dust, dirts and other foreign contaminants which are gathered on the greige fabric during the handling of the fabric.

The process of removing these impurities is called Scouring. This process also increases the absorbency of the cotton fibre.

Cotton, like many nature fibres, has natural coloring. It is a yellowish color fibre. Bleaching is the process by which we remove the natural color of the cotton fibres.

Then after scouring and bleaching, the bio-polish or enzyme wash treatment is done. It is done to remove the hairiness of the cotton fabric and make the fabric smooth and lustrous. Also this process improves the handle and pilling of the fabric.

All these processes are done to remove the unwanted impurities and color in the fabric, increase the absorbency of fabric and improve luster and hand feel of the fabric.

The amount of chemicals required for sourcing and bleaching depends on the hardness of water, strength of chemical, quality of cotton fiber and construction of the fabric. 

Here I am going to share a standard recipe for scouring, bleaching and enzyme bio polishing of cotton knitted fabric in soft flow dyeing machine as done in many dyeing factories.

Scouring and Bleaching Recipe
Liquor Ratio	1:8
Detergent	0.5 g/L
Anti-Creasing agent	0.5 g/L
Anti Foaming agent	0.1 g/L
Stabilizer	0.6 g/L
Sequestering agent	0.4 g/L
Oil Remover	0.5 g/L
Caustic Soda	2.0 g/L
Hydrogen Peroxide	4.0 g/L
pH	10 - 11

Neutralizing and Enzyme Wash Recipe
Liquor Ratio	1:8
Acetic Acid	0.6 g/L
Peroxide Killer	1.0 g/L
Enzyme	0.6 g/L
pH	4.5 - 5

For scouring and bleaching, the pH we need to maintain is 10 to 11.

For neutralizing after scouring and bleaching, we will maintain 1:8 liquor Ratio. We can use acetic acid, 0.6 gram per liter and peroxide killer, 1 gram per liter and

For bio polishing or enzyme washing, we can use enzyme 0.6 gram per liter.

For enzyme wash, the pH we need to maintain is 4.5 to 5.

Scouring and Bleaching Process

To star the process, we first load the fabric into the dyeing machine.

⬇️

Then the required amount of water is loaded.

⬇️

Then detergent, anti creasing, anti foaming and stabilizer chemicals are added. 

⬇️

Then the temperature is raise at 2 degree Celsius per minute to 50 degree Celsius.

⬇️

When temperature is 50 degree Celsius, caustic soda is added.

⬇️

Then the temperature is raised to 70 degree Celsius at the same rate.

⬇️

When the temperature is 70 degree Celsius, then hydrogen peroxide is added.

⬇️

Then the temperature is raised to 98 degree Celsius.

⬇️

At 98 degree Celsius the fabric is treated for 60 minutes.

⬇️

After 60 mins the fabric absorbency is tested. If not ok, then this process may continue till 90 mins. The fabric absorbency is tested every 10 minutes. 

⬇️

When desired absorbency is reached, the temperature is decreased to 60 degrees Celsius at 2 degree Celsius per minute.

⬇️

Then the water is drained out.

Rinsing Process

Then new water is added for rinsing. The temperature is raised to 80 degrees Celsius and the 

⬇️

fabric is rinsed for 10 minutes. 

⬇️

After that  the water is drained out.

Enzyme Wash Process

Then again new water is added 

⬇️

To it Acetic acid is added to bring the P H to 4.5 to 5. 

⬇️

Once this is achieved the temperature is raised to 50 degree Celsius. 

⬇️

Then peroxide killer is added and the fabric is treated for 15 minutes. 

⬇️

Then after that the temperature is raised to 55 degree Celsius. 

⬇️

Then enzyme is added and the fabric is treated for 60 minutes. 

⬇️

After this process is completed the temperature is brought down to 40 degree Celsius and then water is drained out.

Demineralization Process

Then the last process of demineralization will be started by adding water.

⬇️

Then temperature is raised to 40 degree Celsius. 

⬇️

Then detergent is added and Temperature is raised to 60 degree Celsius. 

⬇️

The fabric is treated for 15 minutes. 

⬇️

After that the water is drained out.

After this the cotton fabric pretreatment is complete and it is ready for dyeing.