Mercerized cotton
Mercerized
cotton is produced by a special chemical process that initially gives the
cotton fibers a lustrous appearance while simultaneously strengthening.
Applying the mercerization process to the cotton yarn or fabric during the stimulation causes the fibers to swell, straighten and become round and smooth,
resulting in high luster fibers. Mercerization not only helps the fiber to
increase its potency with dyeing but also improves resistance to disease and
shrinkage. It is also worth noting that mercerized cotton will absorb more
water over time but initially puts more pressure on the water than un-merged
cotton.
Control parameter for mercerization
i.
Caustic soda concentration - (30-32) %
ii.
Caustic soda temperature 16 - 18°C
iii. The concentration of the wetting agent is 5 gm/lt.
iv.
The initial width of the fabric increased to 10cm
v.
The final width of the fabric as per the requirement
vi.
Dwell time 22- 25 sec in caustic soda
vii.
Cigar setting 35 to 45 % as per fabric quality and stretching, for solid grey
35%
viii.
Washing water temperature for yarn-dyed fabric all 50°C and for grey fabric
90°C, 80°C, 70°C, 60°C.
ix.
Inlet freshwater velocity 7 m3/hrs.
x.
Fabric pH after mercerization 5-6
xi.
Neutralization at 60°C with Sirrix NE @ 10 gm/lt.
xii.
Total time needed for Mercerization: 4.50 minutes @ 15 m/min
xiii. 25 seconds submerged in caustic soda solution
@ 15 m/min.
Types of Mercerization
There
are different types of mercerization processes is used in textiles for cotton
processing.
i. Mercerization without tension
Mercerized
cotton fibers swell without tension which increases in length and thickness.
Swelling is caused by alkaline molecules or radicals entering the amorphous
region of the swollen polymer system.
ii. Mercerization under tension
Mercerization
under tension that can only be run over a cotton yarn or fabric causes slight
swelling or fiber contraction. The fiber is grown with increased significance
and uniqueness, albeit a repressive feat. This makes the fiber surface smoother
and more regular, enabling it to reflect incident light more evenly.
iii. Chainless mercerization
This method is called roller mercerization. The machine consists of several
stainless rollers and rubber rollers, relatively large in diameter, tiered
zigzags in close contact with each other inside long holes, designed for
immersion in alkaline solutions of mercerization with low levels. Bound to a
limited length of this type of fabric. Alkaline penetration and fabric swelling
in these early stages, similar devices are used to remove most of the alkali, and to use an open-width soaping machine for further removal and
neutralization.
iv. Chain mercerization
To
compensate for the defects of the roller mercerizing machine, a clip stenter is
used for the post-mercerization treatment after massaging the stenter, where
the widthwise tension is applied but most of the alkali is removed from the
fabric placed on top of the stenter, then the whole alkali is removed and an
open width washing machine is used for neutralization.
v. Cold mercerization
The mercerization process takes place at 15 to 18°C with 31 to 35% caustic soda
solution with a dwelling time of 50 seconds. At this stage, cotton swells best
but also swells. Fast swelling increases the density of the outer edges of the
fibers. Caustic soda viscosity hardens penetration into gray fabrics, resulting
in poor disintegration of the core and lack of uniformity resulting in the reaction
being confined to the surface of the yarn or fabric.
vi. Hot mercerization
The mercerization process takes place at higher temperatures with 30 to 38 %
caustic soda solution, with a dwelling period of 20 to 30 sec. In this process, alkali rapidly penetrates the fabric and improves the core mercerization.
0 Comments