Reactive Dyes offered by us form covalent bonding between dye and fiber and contain reactive group that is often trichlorotriazine (either halo heterocycle/activated double bond) which when applied to fibre in alkaline dye bath helps in forming chemical bond with hydroxyl group on cellulosic fibre. In reactive dyes, chromophore contains substituent which is activated and allowed to react directly to surface of substrate.
Being the most important method for meeting the coloration needs of cellulosic fibres, these dyes can also be applied on:
While applying on nylon, these are applied under weakly acidic conditions. Having low utilization degree in comparison to other types of dyestuff, reactive dyes also bonds to water, creating hydrolysis.
Reactive dyes are categorized by functional group:
Included in Brands
Basilen E & P Cibacron Procion H, HE
Cibacron F & C
Basilen MProcion MX
Levafix Drimarene K & R
Drimarene X & Z Cibacron
activated double bond
activated double bond
Advantages of Reactive Dyes:
Show improved fastness properties
Simplify dyeing procedure
Permanency of the color
Good chemical binding
Allows variety of chromophores to be used
Dyeing cycle and Important factors/phases in Reactive Dyeing:
pH of the substrate prior to dyeing
pH of the dye bath
Pretreatment of the substrate
Solubility of the dyestuff
Quality of water and salt
Washing off sequence
Type of alkali
Types of Reactive Dyes: Bi-functional Dyes: The dyestuffs that contain two groups are known as bi-functional dyestuffs. Here, reactive dyes are constituted in a way to have capacity to react with fibre in more than single way.
Vinyl Sulphone Dyes (VS): These dyes are moderately reactive and have dyeing temperature of generally 600C and pH of 11.5. These are applied by utilizing mixture of soda ash and caustic soda and show excellent fixation properties under proper alkaline conditions.
Monochlorotriazine Dyes (MCT): These are less reactive than vinyl sulphone dyes where reaction takes place in conditions that are more energetic like conditions of typically 800 degree C and pH value of 10.5, which is essential for achieving proper fixation on cellulosic fibres.