Cotton preparation is an extensive process that transforms fluffy, raw cotton into a breathable, dye-ready fabric in a range of weights and constructions. The steps that occur between cotton harvest and dyeing are critical and set many TVF products apart from other cotton fabric options. This article will take you through how to prepare cotton, from sizing and desizing to scouring, bleaching, and mercerization. Each step directly impacts the finished prepared for dye (PFD) cotton fabric.
How is cotton prepared?
In order to dye and finish cotton fabric properly, all impurities must be removed from the fabric.
The process of using an organic or artificial starch to weigh down yarn in order to properly and efficiently knit or weave it.
The process of removing the starch (or sizing) from the fabric. This can also be referred to as slashing.
The process of removing impurities, including wax, oil, and seeds, from the fabric.
A scour natural can also be done, which leaves seeds in the fabric and gives the fabric a natural or vintage look.
The process of brightening the fabric. The process varies by fabric because some fabrics require more bleach or even need multiple bleaches. For example, optical brighteners can be added to the fabric to create an artificial bright white similar to the color of computer paper.
Fun Fact: Bleaching is the only way to fully remove the cotton seeds from fabric.
Don’t be fooled! In an effort to mimic higher grade cotton, silicon is often added to fabric to make it smoother and softer. Once it’s washed down (approx. 10 washes), you might find out that the quality is actually poor.
Note: Silicon finished fabric is not compatible with digital printing and acts as a water repellant.
There are several steps in the cotton finishing process for dyeing. From sizing and desizing to scouring, bleaching, and mercerization, each step plays an integral role in the finishing process for cotton fabric. Depending on the end-use, the cotton fabric will undergo some, if not all, of the finishing process to create the desired results.