You will find different types of reactive dyes which can be generally appropriate for cotton fibre. But molecular structure of cellolusic cotton fibre is complex. Therefore the colors which have more reactivity is ideal for that complicated structure of cotton fibre. The molecular structures of reactive dyes resemble these of acid and easy direct cotton fibre colors, but having an included reactive group.
Usually the structure of reactive dye build with azo anthraquinone triphenodioxazine or copper phthalocyanine chromophores. The main element structural features of a reactive dye are the chromophoric process, the sulphonate groups for water solubility, the reactive group, and the linking class that binds the reactive dyes both right to the chromophore or to some other part of the reactive dye molecule.
All these structural functions can impact the dyeing and fastness attributes of dyed textile material. Most of the industrial Reactive dyes have a complete gamut of colors, several that are especially bright in color. Reactive dyes usually have fairly simple structures that can be synthesised with at the least coloured isomers and biproducts that often boring the shade of the more complicated polyazo direct dyes.
Some colors are hard to obtain with easy chromophores. Dark orange and navy reactive dyes in many cases are relatively boring copper complexes of azo colors and the manufacturing of bright natural reactive dyes generally make. A wide variety of probable fibre-reactive groups has been reviewed and examined by the dyestuff manufacturers.
The last choices for industrial reactive dyes are limited by numerous constraints. The reactive class should show ample reactivity towards cotton fibre, but be of lower reactivity towards water that could deactivate it by hydrolysis.
The hydrolysis of the dye's reactive class is comparable to their reaction with cellulose fibre but involves a hydroxyl ion in water rather than cellulosate ion in the fibre. Furthermore, the dye–fibre connect, after shaped, needs to have ample balance to resist recurring washing. Other factors included are the easy manufacture, the dye balance throughout storage and the cost of the ultimate reactive dye.
Reactive Rroups are of Two Main Types:
(1) Reactive dyes which are responding with cellulose by nucleophilic replacement of a labile chlorine, fluorine, methyl sulphone or nicotinyl causing class triggered by an adjoining nitrogen atom in a heterocyclic ring.
(2) Reactive colors these responding with cellulose by nucleophilic supplement to a carbon–carbon dual connect, generally triggered by an adjoining electron-attracting sulphone group. This kind of vinyl sulphone class is usually produced in the dyebath by removal of sulphate ion from a 2-sulphatoethylsulphone precursor class with alkali.
Though lots of the early reactive dyes had only 1 reactive class in the dyestuff molecule, lots of the newer reactive dyes are bifunctional with two or more identical or various reactive groups reveals some common fibre-reactive groups and the commonly applied abbreviations for these groups. Colors with nicotinyltriazine reactive groups (NT) may respond with cotton on heating below basic conditions.
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