Pectinase
Pectinic components as found in raw cotton mainly consist of
neutral and acidic hetero polysaccharides with different molecular weights and
degrees of esterification. Pectinases capable of hydrolyzing pectinic substances
are generally enzyme complexes containing esterases and depolymerases with
random or terminal activities. Their activity optimum usually lies in the
slightly acidic region at temperatures around 50C. With the conventional
caustic scouring procedure it is not possible to completely remove pectins
especially if they are associated with calcium7.
Cellulase
Cellulases enhance the effect of pectinase to a certain
extent and add softness to the cotton fabric. They often accompany pectinases
in small amounts. If used or scouring cellulases hydrolyze cotton cellulose
lifting off non-cellulosic impurities in the course of the reaction. Typical
fiber damage caused by cellulase cannot be excluded7
Lipase
Cotton waxes consist of various hydrocarbons, fatty alcohols
and acids, and their respective esters which are the major reason for the
hydrophobic nature of the unscoured cotton fiber7.
Another option is scouring with organic solvents during
which these hydrophobic components are extracted. Scouring in presence of a
non-specific lipase can ease the removal of fats and waxes. Many lipase enzymes
are capable of non specifically cleaving various natural lipids and oils,
generating glycerides, glycerol, and short-chained fatty acids7.
Synergism Effect of Cellulase and Protease:
Cellulase and protease mixtures have good synergistic effect
for the scouring of cotton fabric. Cellulose breaks the linkage of cellulose
chain in primary wall and proteases hydrolyse the protein linkage from the
surface of the fiber. The reaction of protease exhibits more sites in the
primary wall for cellulase reaction. These synergistic enzymes combination
removes effectively the protein based impurities with partial hydrolysis of
cellulose. Pections and other impurities which are present in cotton fiber to
about 1.5-2.5% cannot be effectively removed. Pectinase and other specific
enzymes along with above synergistic system can produce scouring efficiency
just equivalent to conventional caustic ecological balance7.
MACHINERY USED
MACHINERY FOR CONTINUOUS PROCESSING
Dornier has developed open width machinery for pretreatment of knitted fabric called EcoCombine. The EcoCombine mercerizing and bleaching range
consists of an impregnation unit and washing sections. The mercerizing unit is
improved by heating and dwelling zone for the peroxide bleach. This not only improved quality but also significant cost advantages both on wet-on-wet and dry-on-dry
applications8.
The parameters and function of machine are:
Fabric speeds in individual sections are accurately
mentioned as per the indication of fabric type and conditions.
It has washing water comparison with set point for washing
unit.
Dancer roll position can be change as per the fabric type.
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