The basic dye and cationic reactive dyes both have amino groups and are suitable for fabric having negative charge (anionic) surface. Want to understand what is the difference between two class of dyes and their dyeing mechanism.
Dear Nisha Chandwani,
Several different attractive forces (or affinity types) may bind a dye to a substrate in a given dyeing method. Basic dyes are used to dye wool and carry a cationic (positive charged) molecular subgroup. In the dye bath, the charged dye molecules are strongly attracted to specific anionic (negatively charged) subgroups on the polymer and during dyeing, the dye molecules migrate into intimate molecule to molecule contact with the polymer molecules. When migration is complete an additional short range non-ionic attraction called Van der Waal bonding further strengthens the fixation and establishes a good ‘wash fastness’ level.
Cationic reactive dyes use similar attractive forces and ionic migration processes to enter the substrate, but they also carry chemically reactive subgroups that enable full non-ionic chemical bonding with the polymer molecules, thereby giving superior wash fastness (see the relevant product literature). Individual reactive dye types have also been developed that have suitable reactivity toward a wide range polymer types.
Basic dyes bear cationic groups, reactive cationic dyes have additional reactive groups that are able to react with fibre reactive groups to form covalent bonds between fibre and dye.
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