Abstract

Dyes are used to color textile fibers, paper, and leather. Today's dyes are almost exclusively synthetic: They are classified chemically and by application class. The properties of the dyes and of the substrates to which they are applied (and their interactions with water as an application medium) lead to the attractive forces that drive the dyeing process, and to an understanding of the thermodynamics and kinetics of dyeing.

Practical dyers control their processes with agitation, heat, and auxiliaries, and aim to achieve a dyeing that is the correct color, level, fast to subsequent use, in an efficient and profitable manner.

The wide range of textile fibers requires different dyes and application processes and conditions. Dyes can be applied in batch or continuous processes, and dyeing machines are also designed to handle material at different stages of the textile chain (fiber, yarn, fabric, and garment). The application of dyes to paper and leather takes into account the ways in which those materials are processed.

Dyeing should lead to a level coloration, but dyes are also printed on textiles to provide colored patterns. Printing is carried out with dyes and with pigments, in a range of styles and with a variety of printing machines.

The fastness of colored materials to many different agencies can be assessed using standard test methods. Dyes themselves can be tested for application performance, and can be analyzed both qualitatively and quantitatively.