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The name AZO has been derived from
the word azote and it meant nitrogen in the ancient
time in French. In Greek, a means not and zoe means
to live. |
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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.
These dyes cannot be applied directly on the fibers
as dyes. Actually, these dyes are produced within the fibers itself. For
this production, first the fiber is impregnated with one component of
these dyes and then the fiber is treated in another component of these
dyes. In this way the AZO dyes are formed. This specialty makes these
dyes very fast to washing within the fabric market.
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.