Denim
Enzymes Neutral
cellulases or Neutrastone Series designed by AETL acting at pH 6-8, acid
cellulases (Denicell Series) acting at pH 4-6 and hybrid cellulases (Addcool
Series) acting at pH 5 - 6.5 are used for the abrasion of denim. There are
a number of cellulases available, each with its own special properties. These
can be used either alone or in combination in order to obtain a specific look.
Application research in this area is focused on preventing or enhancing backstaining
depending on the style required. Backstaining is defined as the redeposition of
released indigo onto the garments. This effect is very important in denim finishing.
Backstaining at low pH values (pH 4-6) is relatively high, whereas it is significantly
lower in the towards neutral pH range. Neutral cellulases are therefore often
used when the objective is minimal backstaining. Hybrid cellulases are effective
tool to save energy cost as processing can be done at ambient or room temperature
conditions. Backstaining
is not the cause of worry now a days due to availability of effective anti backstaining
agents based on chemicals. AETL is one of the first companies to introduce backstaining
removing enzyme (Stain Clear Series), unlike chemical agents which are
used to prevent backstaining. Products are based on blends of different proteases,
lipase and endolase. Enzymes
have opened up new possibilities in denim finishing by increasing the variety
of finishes available. For example, it is now possible to fade denim to a greater
degree without running the risk of damaging the garment. This can be effectively
done by using enzymes like Laccase or peroxidase replacing bleaching chemicals
like hydrogen peroxide or hypochlorite. Peroxidases introduced by AETL
as Ecowash BB are further advantageous over Laccase as it has to be used
in neutral pH 6 - 7 and temperature 50 - 55 0C. The denim industry is driven by
fashion trends. The various cellulases available for modifying the surface of
denim give fashion designers a pallet of possibilities for creating new shades
and finishes. The combination of new looks, lower costs, shorter treatment times
and less solid waste has made abrasion with enzymes the most widely used fading
process today. Incidentally, since the denim fabric is always sized, the complete
process also includes desizing of the denim garment. |