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Textile Dyes »
Dyes for Cellulose Fibers
» Azoic or Naphthol Dyes
Azoic Dyes are also called as Azoic or Nepthol Dyes.
These AZO Dyes consist a group i.e. called AZO group having two nitrogen
atoms and this group (covalent bond) connects atomic ring compounds. The
two Nitrogen atoms are bonded with each other and form -N=N- as part of
their molecular structure. Azoic Dyes are found mainly in three colors
and these are red, brown and yellow. Aromatic amines are the chemicals
from which these dyes are manufactured. Azoic Dyes are classified either according to the
fibers for which these can be used economically or the methods by which
these dyes are applied. When these dyes are used upon the cellulose fabric then initially this fabric starts to suffer from poor rub fastness. This is due to the deposition of the free pigments on the surface of the fabric. This problem can be rectified by boiling the fabric in soap. AZO Dyeing Process is such a process in which the
insoluble azoic dye is produced on the or within the fiber. By treating
a fiber with diazoic and coupling components, this process can be
achieved. After adjusting the dye bath conditions appropriately, the two
above mentioned components react. From this reaction the required
insoluble AZO dye is produced. This is a unique technique. The required
color can be changed by altering of the diazoic and coupling components. |
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