Singeing
This process (cotton only) is
considered one of the processes for finishing preparation, and is only
concerned with cotton woven fabrics. In this process the greige fabric surface
on both sides is subjected to a gas flame which burns the protruding fibers and
results in a smooth surface.
Desizing
In this process the size materials on
the warp threads of the fabric are removed, by passing the fabric in a bath of sulpheric
acid or by using enzymes, soap or hot water depending on the sizing material.
This process is also considered one of the preparation processes for finishing.
Scouring
In this process, the desized fabric is
passed through a cleaning bath, using alkaline or solvent solutions to dissolve
any impurities or soiling on the fabric. Desizing and scouring could be
done in
one operation in some plants. The operation is a preparation step for bleaching
and dyeing. It is possible to do desizing by using hot water and soap.
Bleaching
This process (for natural fibres) is
also one of the preparation processes for finishing, to obtain white colour in
the fabric, by using bleaches, such as hydrogen peroxide or hypochlorite.
Mercerizing
This process (for cotton only) is
also a preparation process for finishing, in which the fabric is treated with
sodium hydroxide to create luster, more strength and higher affinity for dyes
in the fabric. This process could be applied to woven or knitted cotton fabrics.
Dyeing
This process is the finishing process in
which the yarn, fabrics, or garments are treated to add color and intricacy to
the product, using dye stuffs, auxiliaries, reductants, oxidants, …etc. This
process is well known to be a major source of pollution due to the many
chemicals used, and the large quantities of wastewater resulting from the
process, and loaded with pollutants.
Printing
In this process the fabric is printed
with color and patterns, using pigments, dyes, acids, alkalis, softener, binder
and emulsifier solvents. Printing is also one of the major sources for
pollution.
Carbonizing
In this process(for wool),
woven or knitted wool fabrics are treated with sulphuric acid to remove the
vegetable cellulosic matter naturally existing in wool fibers.
