Preparation Stage
Fabric purification removes natural and processing impurities from raw fibers before dyeing or printing begins. This substrate pre-treatment includes desizing, scouring, and bleaching, which are necessary to make the fabric absorb dye uniformly. If the fabric is not prepared correctly, the subsequent color application will be blotchy and uneven.
This is the foundation of high-quality fabric finishing.
Process Flow
The sequence of preparation steps depends on the fiber type and the final application of the fabric. For cotton fabrics, desizing is carried out first to remove the starch applied during weaving, followed by scouring to remove waxes. This substrate pre-treatment must be completed before bleaching can occur.
The desized fabric is tested for absorbency before proceeding.
Absorbency Check
Laboratory testing evaluates the efficiency of the preparation process by measuring the water drop absorption time. A prepared fabric should absorb a drop of water in less than two seconds. If the absorption time is too long, it indicates that residual waxes are still present, which will block the dye.
The substrate pre-treatment must be repeated if the test fails.
Fibre Strength
Alkaline chemicals used in scouring can damage natural fibers if the temperature and time are not controlled. The mill must monitor the tensile strength of the fabric to ensure it is not degraded during the preparation stage. This balances absorbency against fabric strength.
