This document discusses mercerizing, which is a process that treats cellulosic materials like cotton with a concentrated alkali solution. Mercerizing improves properties like luster, strength, dye uptake, and dimensional stability. It involves padding fabric with an alkaline liquor, washing, neutralizing with acid, and drying. Physically, it changes the cotton fiber's cross section from bean-shaped to circular and removes convolutions. Mercerizing can be done continuously using a J-Box system that passes fabric through alkali and acid baths over several minutes.
3. Treatment of cellulosic material with higher concentrated
alkali for short period at low temperature.
Mercerizing is done after bleaching operation. Bleaching is
enough for prepared the fabrics for dyeing and printing but
mercerizing is done for adding some advantage to the fabric.
Luster and strength of the fabric increases for mercerizing
process. Cotton mercerizing is the most popular operation.
4.
5. To improve elasticity
To improveluster of cotton material
To improve strength and mechanical properties
To improve dye ability and moisture
absorbency
To improve dimensional stability of material
6. FLOWCHART OF
MERCERIZATION:
For white finished goods, mercerizing is done by the Following sequence:
Fabric after scouring and bleaching process
Padding in alkaline liquor
Washing
Neutralization in acid solution
Washing
Drying
7. PHYSICAL CHANGE:
Improvement in strength
Improvement in luster
Change in cross section from bean
shape to circular shape
Change in longitudinal view
convoluted to cylindric
8. Formation of cellulose -
Improvement of moisture
regain
Improvement in dye uptake
9. INCREASE INTENSILE STRENGTH
Removal of convolutions removes the weak spots at the point of
reversal.
Alignment of fibers in the new configuration after treatment with caustic
soda
More parallel and compact due to removal of convolutions
Penalization and compactness is much better on application of tension
Improvement in strength is much higher in case of tension mercerization
compared to slack mercerization
10. WHAT HAPPENS TO COTTON DURING MERCERIZATION:
I. Swilling of fibre take place
II. Cellulosic chains gets rearrange and become
parallel
III. De-convolution
IV. Cross sectional bean shape to circular shape.
11. Application of caustic soda solution
around at room temperature
A dwell period of 55sec on an average
Tension at both direction
Finally washing off of alkali from the treted fabrics or
yarn
12. o Yarn or fabric can be mercerized by J-Box.
o Mercerizing is a continuous process.
o At first fabric is hanked by the roller in a J-Box.
o Fabric is passed through a solution which contains 23°/o
NaOH at room temperature.
o Fabric is passed for 4-5 minutes.
13. METHODS OFAPPLICATION:
o Then fabric is squeezed by the squeezed
roller and washing is done in a bath at 85
degree Celsius.
o Then it also immersed in an acid solution
bath which contain 5% CH3COOH.
o After that is washed in another bath at 85
degree Celsius. By this way we can get a
mercerized fabric