Dyeing and Printing

Dyeing And Printing 3(2+1)

Lesson 05 : Classification Of Dyes

Optical Brightners

• These so called dyes are also called fluorescent whiteners or optical brighteners. The whiteness is really caused by absorption of u.v light and reflection of visible blue light.
• These are also called as colour less dyes.
• These are usually used for white textile materials making these appear whiter and brighter.
• Optical brighteners are available for cotton, acrylics, wool, acetate and nylon. They may be applied during bleaching before resin finishing or with resin.
• OBA’s have chemical structure, which are similar to dyes.
• Domestic laundry detergents usually contain fluorescent brighteners but these are only suitable for cellulosic fibre textile materials.