Whitening Process for Cotton and PC Blended Fabric

What is Fabric Whitening Treatment?
Whitening is a chemical treatment, which is applied on fibers, yarns or fabrics to make white at a desired level by bleaching and OBA treatment. Whitening is done by removing irregular natural color of fibers, yarns or fabrics.

Factors Influencing for Fabric Whitening Process:
The factors influencing whitening process are as follows :

1. pH of the bath
2. Temperature of the bath, and
3. Time required for the process.

Process Requirements for Fabric Whitening:

Equipment Used:
Three types of Thies machines are used for whitening process. These are:

1. Mini-soft
2. Eco-soft
3. Luft-roto

Accessories Used in Whittening:
Key accessories used in whitening process are:

1. Mixing tank
2. Machine Tank
3. Bohme meter
4. pH meter
5. Eye protecting glass
6. Hand gloves
7. Sewing machine
8. Hand lifter for carrying the batch, and
9. Gum boot.

Materials / Chemicals Used:
Following materials/chemicals are used in the whitening process:

1. Water
2. Steam
3. Compressed Air
4. Wetting agent
5. Detergent
6. Sequestering agent
7. Acid
8. Anti-creasing agent
9. Optical Brightener for Cotton & Polyester
10. Caustic Soda,
11. Hydrogen per Oxide, and
12. Stabilizer, etc.

Operation Procedure:

Whitening process for 100% cotton:
Steps of whitening process for 100% cotton:

The sequence for whitening process for 100% cotton fabric is as follows:

1. Take water in bath at required level
2. Add Detergent, Sequestering Agent, Anti-creasing Agent, Stabilizer
3. Circulate the fabric for 5 minutes at 50ºC
4. Add Caustic Soda and circulate for 5 minutes at 50ºC
5. Add Hydrogen per Oxide and circulate for 5 minutes at 50ºC
6. Add Optical Brightener agent and raise the temperature at 100ºC
7. Continue circulating the fabric for 50 minutes at constant temperature (100ºC)
8. Circulate the fabric and decrease the temperature at 60ºC
9. Check the shade with approved shade
10. Rinse and Drain
11. Add Acetic acid and circulate for 10 minutes at 50ºC
12. Drain
13. Unload

Graphical representation of whitening process of 100% cotton:
The whitening process for 100% Cotton can be graphically presented as below:

Whitening process for polyester cotton (PC) blended fabric:
Steps of whitening process for polyester cotton blended fabric:

The sequence of whitening process for polyester-cotton blended fabric is as follows:

1. Take water in bath at required level
2. Add Detergent, Sequestering Agent, Anti-creasing Agent, Stabilizer
3. Circulate the fabric for 5 minutes at 50ºC
4. Add Caustic Soda and circulate for 5 minutes at 50ºC
5. Add Hydrogen per Oxide and circulate for 5 minutes at 50ºC
6. Add Optical Brightening Agents and raise the temperature at 110ºC
7. Continue circulating the fabric for 30 minutes at constant temperature (110ºC)
8. Circulate the fabric and decrease the temperature at 60ºC
9. Check the shade with approved shade
10. Rinse and Drain
11. Circulate the fabric for 10 minutes at 80ºC
12. Drain
13. Add Acetic acid and circulate for 10 minutes at 50ºC
14. Drain
15. Unload

Graphical representation of whitening process for polyester cotton blended fabric:
The whitening process for polyester-cotton blended fabric can be graphically presented as below:

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