There are many methods for producing colored fabrics, the most common industrial methods are the following:
1. Pre-colored yarn is used in weaving or knitting processes. The yarn is colored with dyes through a dyeing process or through a masterbatch from the spinning process.
2. Use appropriate dyes to dye the fabric. There are several categories of textile dyes, each suitable for specific fibers. The main categories are: acidic, alkaline, dispersive, reducing, reactive, direct and sulfur.
3. Print the fabric using suitable dyes or pigments.
A dye is a molecule with a specific color that remains stable under a variety of conditions. These molecules can attach to fibers through physical or chemical bonds. The bond between the dye and the fabric should remain intact throughout the life of the textile. The dye must be soluble in water during at least one stage of the dyeing process. Dyes are used in at least one of the following dyeing methods:
1. Production of masterbatch, which is subsequently used in fiber spinning to create colored yarn.
2. Yarn dyeing
3. Fabric dyeing
4. Printing
Disperse dyes are a category of textile dyes which are suitable for hydrophobic or low-hydrophilic fibers such as Nylons and Polyester fibers. The main use of Disperse dyes are in spinning, dyeing, or printing of polyester goods. Disperse dyes have a very low solubility in water and thus dyeing with these types of dyes is only possible by using carriers or at a temperature higher than 110°C.
The molecular weight is a significant parameter in Disperse dyes’ behavior. Based on this parameter, they are divided into the following groups:
1. High energy -S- dyes, which have low molecular weights and thus having a very good leveling property, therefore resulting a high dyeing rate and a low sublimation fastness property. Dyeing of this group can be conducted by carriers or HT dyeing and are recommended for dyeing pale shades and filament fabrics.
2. Medium energy -SE- dyes, which their molecular weight is higher than -S- dyes. It has a moderate levelling, dyeing rate and sublimation fastness properties.
3. Low energy -E- dyes, which have the highest molecular weight. Therefore, their dyeing rate and levelling is low and sublimation fastness is high.