The dyeing of cotton fabric with irradiated dye solution is also time dependent.
When cellulose fibre is dyed with a dye for sufficiently short time,
the dye enters the fibre structure
and is generally distributed in the interior of the fibre while it remains only on the surface with slight diffusion,
when dyed for a long time.
Dyeing was carried out at different times between 20 and 40 min.
It is found that colour strength values rise with the increasing dyeing time up to 30 min and then decrease.
Results shown in Fig. 3 indicated that for a long time
of dyeing insoluble impurities may cause sorption of dye on
fabric along with dye, due to which low colour strength and
dull shades are found from spectraflash spectrophotometer
(Kaczmarek et al., 2004). But at 30 min of dyeing, sorption
occurs on the surface of the cotton. The results shown in
Fig. 3 reveal that 30 min is the optimum time of dyeing.