1. Desizing is the process of removing size material from warp yarns in woven fabrics to facilitate weaving. Sizing agents are selected based on fabric type. 2. Size comes from coating warp yarns with sizing agents before weaving to decrease breakage and improve productivity. However, sizing agents resist dyes and chemicals used in textile processing, so must be removed before wet processing. 3. Common desizing methods include acid desizing using dilute acids, enzymatic desizing using enzymes to degrade starch size, and desizing on a jigger using hot water and amylase in an impregnation stage followed by washing.

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2. Desizing:
It is the process of removing the Size material from the
warp yarns in woven fabrics to facilitate the process of
weaving. Sizing agents are selected on the basic of type of
fabrics.. Desizing is an essential stage of all textile
processing, in which ‘size’ is removed from fabric before
completing the pre-treatment process, which is necessary
before dyeing, printing and finishing.

3. OBJECTS OF DESIZING:

4. Where does the size come from?
Before yarn is converted into fabric, the ‘Warp’ yarns
are coated with sizing agents which decreasing
breakages on the loom and improves productivity.
However the sizing agents often resist the dyes and
chemicals commonly used in textile processing, so
they have to be thoroughly removed before any wet
processing can take place.

7. Acid Desizing:
Cold solutions of dilute sulfuric or hydrochloric acid
s are used to hydrolyze the starch. however, this h
as the disadvantage of affecting the cellulose fiber
in cotton fabrics

8. Enzymatic Desizing:
Enzymatic desizing is the classical desizing process of degrading starc
h size on cotton fabrics using enzymes. Enzymes are complex organic
bio-catalysts, formed by living organisms, that catalyze chemical reacti
on in biological processes. A small quantity of enzyme is able to decom
pose a large quantity of the substance it acts upon. Enzymes are usuall
y named by the kind of substance. Amylases is the enzyme that hydrol
yses and reduces the molecular weight of amylose and amylopectin in
starch.

9. Desizing on a jigger:
It is a simple method where the fabric from one roll is
processed in a bath and rewound on another roll. Fir
st, the sized fabric is washed in hot water (80-95°C).
The desizing liquor is then adjusted to pH 5.5-7.5 .
The amylase is added in an impregnation stage and
degraded the starch in the form of dextrin's. Then re
moved by washing two minutes. The jigger process i
s a batch process. In the reaction time for the enzym
e may be as little as 15 seconds.

10. Oxidative Desizing:
In oxidative desizing, the risk of damage to the cellulose fib
er is very high, and its use for desizing is increasingly rare.
Oxidative desizing uses sodium or potassium sulphates or
sodium bromite as an oxidizing agent.

11. Factors of Size Removal Efficiency:
The factors on the efficiency of size removal depe
nds,
are as follows:
1.Type and amount of size applied
2.Viscosity of the size in the solution
3.Nature and the amount of the plasticizers
4.Fabric construction
5.Method of desizing
6.Method of washing.

12. Method of testing:
1.The more scientific method is One or two drops of the
solution are put on the desized fabric and rubbed gently. In a s
hort time the color of the spotted area changes. The change in
color is assessed visually.
2.The weight loss can be used as criteria for testing of desizin
g efficiency. The weight loss is of the order of 7-10%.