Page 54 - Advances in Textile Biotechnology

Developments in enzymatic textile treatments 33

There has been a great deal of research on the application of enzymes in
wet textile processes. However, work in which the role of mechanical energy
is also included is rather rare. There are some data on the role of mechan-
ical energy in wet textile processes, but these are mainly related to fabric
wash processes (Donk, Van der et al., 1998, Warmoeskerken and Boom
1999). Lenting and Warmoeskerken (2001) discussed the role of mechanical
shear in enzymatic textile treatment. This work was focused on the removal

of fibril pills during the treatment of cotton fabric with cellulose. Agrawal

et al. (2008) were the first to show unambiguously that there is strong syn-
ergistic relation between the performance of enzymes in wet textile pro-
cesses and the mechanical energy applied. They also showed that the
mechanical action can be delivered by ultrasound resulting in a very effec-

tive and efficient enzymatic treatment process (Agrawal et al., 2007). Data
on the suboptimal adsorption of enzymes at the surfaces of the textile cap-
illaries is not available. In this chapter, the phenomena mentioned here are
discussed and models that describe them are presented.

2.2 Current processes for the pre-treatment
of cotton

In cotton pre-treatment, different types of installed base and processing are
necessary to realize sufficient desized, scoured and bleached fabric for

consecutive treatments such as dyeing, printing or fi nishing.
The process steps for the pre-treatment of cotton are listed below.

1 Desizing: the removal of starch from the warp yarns.
2 Scouring: the removal of waxes and pectin for suffi cient hydrophilicity.
3 Bleaching: the decolourization of the natural ‘grey’ colour of cotton.

If possible, one or more process steps are combined. For the pre-treatment,
various types of processes can be distinguished.

2.2.1 Full-continuous pre-treatment
The full-continuous process is done on two types of installed base. The fi rst
type is open width form. For the consecutive process steps, the fabric is
impregnated with processing agents on an impregnation unit. This unit
consists of rollers that guide the fabric into and out of the bulk. During the
impregnation, the fabric is squeezed at least once. After impregnation, the
fabric is incubated in a steamer where the fabric is guided over rollers. After
incubation, the fabric is rinsed in washing compartments. A washing com-
partment consists of rollers to guide the fabric into and out of the bulk to

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