REACTIVE VS BASED DYES are Reactive Dyes possessing Vinyl sulphone as the reactive group. In presence of alkali, these dyes chemically react with the hydroxyl group of cellulose and form firm, convalent linkages. These dyes are versatile enough to suit different dyeing methods. Results are excellent and shades come clean and brilliant with no variation in dyeing as well as in printing.

VS dyestuff posses poor affinity for cellulosic fibres in absence of salt and alkalis. For this reasons, they are suitable for use on pad. Their substantivity can be increased by addition of glauber’s salt or common salt and alkali, making the dyestuff suitable on all conventional dyeing machines for loose material, yarn in hanks and packages and piece goods. The dyeing methods may therefore, be classified under the padding and exhaust processes, standing baths are not recommended, as in alkaline medium inactivation of the dyestuffs by reaction with water takes place as a side reaction.

The main features of VS dyes are:

1. Process excellent brightness and good wet fastness.
2. They are dischargeable.
3. They are suitable for exhaust & different pad dyeing methods and discharge printing.
4. Ease of washing off unfixed dyestuffs i.e. minimum staining of the white grounds in printing.
5. They are applicable at 40^oC and 60^oC.