Now You Know Whitening Agent: Properties, Function, Mechanism and Usages (Part-6)

Whitening Agent: Properties, Function, Mechanism and Usages (Part-6)

Authors: Md. Mosharaf Hossain
Kiriti Kingkar Mondal
Tawhidul Islam
Dept. of Textile Engineering
Primeasia University, Dhaka

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FBA for Cellulogic Fiber
Tiponal BV, 2B, GS, RBN, 4BM. Applied by exhaustion or padding method. Exhausts at pH 8-11 or higher. Salt should be used for exhausting Tiponal BV on the fiber. Tiponal 4BM is suitable for application by the padding technique. Blancophor CL is intending for whitening cellulogic fiber. It is stable to Hydrochloride and Chloride Bleach bath, so that it may be applied while bleaching with these bleaching agents. Fluorite BW stables alkaline hydrogen peroxide and per salt bleach and hence can be applied during bleaching. It can be applied by exhaust dyeing method. Since it have affinity for cellulogic fiber. Uvitex CK stable to hard water.

FBA Polyester Fiber
Fluorite XMF intended for PES. Available in past form. Applied at 100c with carrier. Thermosol used at high temperature pad-dry-bake process. Palanil white G liquid. Blancophor EBL of Bayer AG. Uvitex SEB-nonionic, micro fore aqueous dispersion all used in this purpose.

Process Requirements

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 Whitening
Key accessories used in whitening process are :

• Mixing tank
• Machine Tank
• Bohme meter
• pH meter
• Eye protecting glass
• Hand gloves
• Sewing machine
• Hand lifter for carrying the batch, and
• Gum boot.

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

• Water
• Steam
• Compressed Air
• Wetting agent
• Detergent
• Sequestering agent
• Acid
• Anti-creasing agent
• Optical Brightener for Cotton & Polyester
• Caustic Soda,
• Hydrogen per Oxide, and
• Stabilizer, etc.

Operation Procedure

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 500C .
4. Add Caustic Soda and circulate for 5 minutes at 500C .
5. Add Hydrogen per Oxide and circulate for 5 minutes at 500C.
6. Add Optical Brightener agent and raise the temperature at 1000C .
7. Continue circulating the fabric for 50 minutes at constant temperature (1000C) .
8. Circulate the fabric and decrease the temperature at 600C .
9. Check the shade with approved shade.
10. Rinse and Drain.
11. Add Acetic acid and circulate for 10 minutes at 500C.
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 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 500C
4. Add Caustic Soda and circulate for 5 minutes at 500C
5. Add Hydrogen per Oxide and circulate for 5 minutes at 500C
6. Add Optical Brightener agent and raise the temperature at 1100C
7. Continue circulating the fabric for 30 minutes at constant temperature (1100C)
8. Circulate the fabric and decrease the temperature at 600C
9. Check the shade with approved shade
10. Rinse and Drain
11. Circulate the fabric for 10 minutes at 800C
12. Drain
13. Add Acetic acid and circulate for 10 minutes at 500C
14. Drain
15. Unload 

 

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