Textile bleaching

All raw rextile materials when they are in natural form they are called as 'greige' material. This greige material will be with its natural color, odour and impurities that are not suitable for clothing materials. Not only the natural impurities will remain on the greige material but also the add-ons that were made during its cultivation/manufacture/growth in the form of pesticides, fungicides, worm killers, sizes , lubricants etc.

The removal of these natural coloring matter and add-ons during the previous state of manufacturing is called scouring and bleaching. Scouring is the first wash with or without chemicals, at room temperature or at suitable higher temperatures with the addition of suitable wetting agents, alkali and so on.

The next process of decolorization of greige material in to a suitable material for next processing is called bleaching. Bleaching of textiles can ne classified in to oxidatibe bleaching and reductive bleaching.

Generally oxidative bleachings are carried out using sodium hypochlorite, sodium chlorite or hydrogen peroxide. Natural fibres like cotton, ramie, jute, wool, bamboo are all generally bleached with oxidative methods.

Reductive method of bleaching is done with Sodium Hydrosulphite, a powerful reducing agent. Fibres like polyamide, Polyacrylics and Polyacetates can be bleached using redcutive bleaching technlogy.

You will have detailed methods, tips and other useful information from the follwing referred website. [1]