In the Mercerization process, cotton fabric or yarn is treated with a cold concentrated solution of sodium hydroxide for one minute or less. In this process cotton fibers swell, untwist and their bean shaped cross section changes into a round form.
Mercerization improves the following properties of the cotton fabric.
1. Strength would be increased to 15-25%.
2. Enhanced luster. Greater affinity to water.
3. Dyes and other chemical finishes.
4. Shrinkage control in both the direction of the fabric.
Fabric is padded with about 20-25% NaOH solution containing a wetting agent. Fabric is passed over several cans to allow a doweling time of approximately one minute. During this time, NaOH will penetrate the fibres and react with them. At this stage the tension is applied lengthwise. The fabric is then placed on a “Stenter” machine and is pulled to its desired dimensions.
