Chemical Dyes, contrary to aniline dyes, which have no
stability, are permanent against light and washing and
also are very economic.
dyeing by this type of dye, temperature of dyeing bath
must be lower than 55 to 60 degree C, as the bath liquid
is acidic and higher temperature might effect on wool
quality and make its color non-homogenous. To avoid
un-level color of wool, an amount of sodium sulfate is
added to bath.
dyeing, at first particular dye is weighed proportional to
pile weight, by scale or balance. Then 10% to 20% of
sodium sulfate, 2% to 4% Sulfuric acid and 1/40 of water
volume, proportional to wool weight, are prepared. Bath is
completely mixed, so that dye spreads to the all points of
which has been carefully washed, is entered to bath. It
takes about 30 minutes to start boiling and it remains in
bath for an hour in boiling condition. Then, it is
carefully washed and dried.
powder dyes, kept in special jars in workshops, are: Red,
dark blue, green, black, olive, pink, yellow and brown.