Calculation of Bleaching Recipe

Bleaching:
Bleaching is a chemical treatment employed for the removal of natural coloring matter from the substrate. Also, absorbency is increased because sodium hydroxide is used to increase the pH value and remove oil, fat wax, etc. This is an oxidation process where the natural color of the fabric destroyed. For any type of dull shade, this process is not necessary but for the brilliant shade this process must be used and for the medium shade light bleaching process is used. In this article, I will provide a calculation of the bleaching recipe with the amount of water and chemical used in cotton bleaching.

Like all-natural fibers, Cotton has some natural coloring matter. That confers a yellowish-brown color to the fiber. The objective of bleaching is to remove this coloring material and to confer a white appearance to the fiber. Additionally to an increase in whiteness. Cotton Bleaching results in an increase in absorbency, levelness of pre-treatment, and complete removal of seed husks and trash. Bleaching is the essential step in the pretreatment of the Textiles Industry. It helps ‘whiten’ the textile material by removing undesired inherent coloring components.

Calculation of Bleaching Recipe

Calculation:

Sample weight = 9.64 gm

………………….Total liquor x Recipe amount (gm/L)
Chemical = …………………………………………………………
………………………..1000 x Stock Solution %

Total liquor = 9.64 x 10 = 96.4 ml

…………….96.4 x 9
H₂O₂ = ……………….. = 8.676 ml
………….1000 x 10 %

………………….96.4 x 4.5
Stabilizer = ……………….. = 4.338 ml
………………..1000 x 10 %

…………………96.4 x 8
NaOH =……………………….. = 7.712 ml
………………1000 x 10 %

………………….96.4 x 5
Na₂CO₃ = …………………. = 4.82 ml
………………..1000 x 10 %

…………………….96.4 x 1
Detergent = ………………….. = 0.964 ≈ 1 ml
…………………..1000 x 10 %

……………………………………96.4 x 1
Sequestering agent = ……………………. = 00.964 ≈ 1 ml
……………………………………1000 x 10 %

…………………………..96.4 x 1
Wetting agent =…………………… = 0.964 ≈ 1 ml
………………………..1000 x 10 %

……………………………96.4 x 1
Anti creasing = …………………….. = 0.964 ≈ 1 ml
………………………….1000 x 10 %

Water =96.4- (8.676+4.338+7.112+4.82+1+1+1+1)
= 67.454
≈ 68 ml

Advantages of bleaching:

1. Permanent whiteness.
2. The high degree of brightness.
3. Negligible degradation of fiber.
4. Lower environmental impact of wastewater.
5. Versatile bleaching agent for cellulosic, synthetics, and blends especially poly-cotton blends.
6. Non-sensitive to metal ions such as iron and water hardness under acidic conditions.

Author of this Article:
Mustaque Ahammed Mamun
Department of Textile Engineering
Dhaka University of Engineering & Technology (DUET)
Cell: +8801723300703
Email: [email protected]

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