What preparation is needed before dyeing cotton?

Read through these articles to learn about scouring, bleaching, mercerizing, and the final steps of the preparation process.

• Sourcing

• Bleaching

• Mercerizing

• Final Steps

Sourcing

Preparation of cotton fibers, yarns, and fabrics to undergo dyeing and finishing processes is critical because many problems that appear later are often traced back to inadequate preparation. regardless of the substrate — whether a fiber, a yarn, a fabric, or a whole garment — the primary step of preparation is scouring to get rid of unwanted impurities. Scouring also improves absorbency and ensures that the cotton is uniformly clean.

Bleaching

Bleaching

Another major preparation process is bleaching, to supply a consistent white base, in order that light or bright colors are often achieved. Various chemicals can produce the whiteness achieved by bleaching, but the foremost commonly used is peroxide . Peroxide bleaching offers distinct advantages beyond good whiteness, because it is economical and versatile to use.

Mercerizing

A third process often used with cotton fibers is mercerization, which changes the body of the cotton fiber and thereby its physical properties and appearance. In mercerization, the substrate is exposed to a concentrated solution of sodium hydroxide , usually under tension. Mercerization changes the cotton fiber’s cross-sectional shape and morphology.

Mercerizing Machine

Final Steps

The final step within the preparation of any substrate is rinsing and neutralizing any chemistry that has been used. to make sure that the fiber is clean, the solubilized matter created during scouring must be removed. the ultimate pH of the substrate must be neutral, with none residual alkaline salts.