Лако-красочные материалы — производство

Dyes may be classified according to chemical structure or by their usage or appli­cation method. The former approach is adopted by practicing dye chemists, who use terms such as azo dyes, anthraquinone dyes, and phthalocyanine dyes. The latter approach is used predominantly by the dye user, the dye technologist, who speaks of reactive dyes for cotton and disperse dyes for polyester. Very often, both terminologies are used, for example, an azo disperse dye for polyester and a phthalocyanine reactive dye for cotton.

Chemical Classification. The most appropriate system for the classification of dyes is by chemical structure, which has many advantages. First, it readily identi­fies dyes as belonging to a group that has characteristic properties, for example, azo dyes (strong, good all-round properties, cost-effective) and anthraquinone dyes (weak, expensive). Second, there are a manageable number of chemical groups (about a dozen). Most importantly, it is the classification used most widely by both the synthetic dye chemist and the dye technologist. Thus, both chemists and technologists can readily identify with phrases such as an azo yellow, an anthraquinone red, and a phthalocyanine blue.

The classification used in this chapter maintains the backbone of the Colour Index classification, but attempts to simplify and update it. This is done by show­ing the structural interrelationships of dyes that are assigned to separate classes by the Colour Index, and the classification is chosen to highlight some of the more recent discoveries in dye chemistry [4].

Usage Classification. It is advantageous to consider the classification of dyes by use or method of application before considering chemical structures in detail because of the dye nomenclature and jargon that arises from this system.

Classification by usage or application is the principal system adopted by the Colour Index [5]. Because the most important textile fibers are cotton and poly­ester, the most important dye types are those used for dyeing these two fibers, including polyester-cotton blends (see Chapter 4). Other textile fibers include nylon, polyacrylonitrile, and cellulose acetate.