b) Knit Mercerization 

1). Open Mercerization 

To carry out this types of mercerization on circular knits, it is required to first open the tubular knits using tubular slitting device as shown in the figure.

For mercerization purpose the open knits are glued to make artificial selvage just like woven fabric. If opened knits are not glued, it is possible it would curl. Due to curling mercerization would be difficult.  After gluing (making artificial selvage) the mercerization is carried out similar to woven cotton fabric.

It is important to control the change in dimension of cotton knits. To control dimensions, it is needed to keep residual shrinkage below 2%. Another important factor in knits is that during processing there should not be any deformation in the loops. Therefore, while mercerizing, one has to take care of these factors. Beside this mercerization should bring good absorbency, softness and luster in the knits.

                 

2). Closed Mercerization (Tubular Mercerization) 

As its name indicates, in such cases there is no need to open knits. The mercerizing is carried out in the tubular form. In this type of mercerization two tubular fabrics in flat form is fed in to the machine side by side.

During mercerization, strong pressure/tension is applied on longitudinally direction to the folds of the two edges of the long sides of the fabric. Due to this tension some time it causes differences in yarn density on both faces of the knits, which results edge mark on the inside of the fabric. This can be avoided by controlling pressure/tension and adjustment of nip. Other methods that prevent the formation of edge marks include introducing air to the inside of the tube at strategic spots due to which the knit expands to a cylindrical shape, setting several round plastic blades or rings with alterable circumferences at intervals inside the tubular knit, or inserting a bar-shaped frame inside, thus preventing the fixing of the edges during the treatment, and also expanding the width of the fabric.