Optical Brightening Agent Application
topic
Optical brightening agent application uses pad or exhaust bath application of fluorescent stilbene, benzimidazole, or coumarin derivatives that absorb UV radiation at 340 to 370 nanometres and re-emit visible blue light at 420 to 440 nanometres to compensate for the yellow background of natural fibres, achieving CIE whiteness values above 120 for treated cotton and above 80 for treated polyester compared to untreated fabric values below 60.
Role
Achieves the brilliant optical whiteness required for white textile consumer products including shirting, bedlinen, underwear, and sportswear through fluorescent brightening that converts invisible UV radiation to visible white light, with OBA selection and concentration optimisation for each fibre type providing the maximum whiteness development at minimum chemical cost while avoiding the shade dullness caused by OBA overloading that reverses the whitening effect.