Application of OBA on Cotton Knitted Fabric in one Exhausts Method

Last updated on July 16th, 2023 at 10:36 am

Optical Brightening Agents (OBA) are colorless or very pale yellow colored organic compounds which when added to a substrate increase the apparent reflectance in the visible by converting ultra-violet radiation into visible light and thus increase the whiteness or brightness.

OBA application on textile fabric

An OBA can be called a colorless dye which has some substractivity for the fibre on which is to be used.

Optical brightening agents can also be called:

  • Fluorescent brightening agent
  • Physical brightening agent
  • Brighteners
  • White dyes etc.

Fibre and Fabric

Fibre: 100% cotton

Fabric: Knit fabric


Here, one of the exhaust methods is used.

Instruments and glass ware

  • Beaker
  • Glass rod
  • Measuring cylinder
  • Bowl
  • Electric balance
  • Scissor
  • Sample dyeing
  • Water shaking bath
  • Tumble dryer

Instruments and materials needed for washing test

  • SDC recommended multi-fibre fabric
  • Water shaking bath
  • Thermometer
  • Dryer
  • Color matching cabinet
  • Sewing machine
  • Grey scale

Reagent required for washing fastness test

  • ISO reference detergent
  • Sodium carbonate
  • Distilled water
  • Pipette


Optical brightening agent: 3%

NaOH: 4gm/l

H2O2: 8gm/l

Wetting agent: 2gm/l

Stabilizer: 1gm/l

Sequestering agent: 1gm/l

Sample weight: 5gm/l

M : L: 1 : 20

Total liquor: 100 cc

Necessary Calculation

NaOH Stock solution 4% = (10 X 100 X 100)/(1000 X 4) = 10 CC

H2O2 Stock solution 8% = (8 X 100 X 100)/(1000 X 8) = 10 CC

Wetting agent Stock solution 2% = (2% X 100 X 100)/(1000 X 2) = 10 CC

OBA Stock solution 5% = (5 X 3%)/(5%) = 3 CC

Water required = { 100 – (10 + 10 + 10 + 3)} CC = 67 CC

Process Description

  • The dye bath is set at 300C and add sample, wetting agent stabilizer.
  • The temperature is raised at 600C and added NaOH and kept it for 5 minutes.
  • Add H2O2 at 700C for 5 minutes.
  • Raise the temperature 80 – 1000C by 1.50C/min for 60 minutes.
  • Check the shade and cooling down at 500C.
  • Drop down the bath and wash sample at running water and do not squeeze.


Recipe: Acetic Acid 1gm/l

Necessary Calculation

Acetic Acid 1% stock solution = (1 X 100 X 100)/(1000 X 1) = 10CC

Water requires = (100 – 10) CC = 90 CC


Neutralization is at 600C temperature for 10 minutes


  • Stock solution should be made carefully.
  • Time and temperature should be maintained carefully.
  • Soda, OBA should be properly dosed.
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He is Abu Sayed, the founder of the blog site Textile Apex. He is a Textile Engineer having eight years plus practical experience in the Textile and Clothing industries. With a deep love for fashion and a keen eye for detail, he combines his creative flair with extensive knowledge to offer insightful and engaging content to his readers.
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One thought on “Application of OBA on Cotton Knitted Fabric in one Exhausts Method

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