Colorant is in accordance with DIN 55943, the collective name for all colorants.
Colorants are classified according to their chemical composition in inorganic and organic colorants. In both groups can be distinguished in each
- The solubility in pigments and dyes,
- To the origin in natural and synthetic colorants and
- After the color quality in black and white or colorful colorants
It adds special systems such effect or fluorescent colorants.
Classification by solubility
The organic colorants (insoluble ) or dyes ( soluble) classified according to their solubility in pigments, the practical application of the respective medium is used. Inorganic colorants are almost always classified as pigments.
Pigments are insoluble in the application medium and are preferably used for emulsion paints, coatings, plastics, printing inks and artists' colors. Inorganic white pigments such as titanium dioxide are preferably used today as a filler in papermaking. Preferred pigments are real high to emigrating to prevent migration. Not all pigments are completely resistant to migration in each colored system. The presence of particles as pigments usually have a higher level of authenticity than colors.
Dyes in the application medium, in water or organic solvents, insoluble. The use of the solvent used is determined by the application and the substrates. Typical applications are the coloring of textiles or textile fibers are used as colorants in writing implements and ink-jet inks, or for ease of coloring of paper and plastics.
Depending upon how the colorant behaves in the intended matrix or substrate, there is a division into a pigment or dye. A single chemical substance may be jenach reference system or chemical groups pigment and dye.
It is true for the coloring of indigo jeans dyed product is as a pigment, since it is insoluble in the cotton fiber, and this results in the low rubbing. In order to dye with indigo it is vatted. Wherein vatting of the indigo is reduced to soluble " leuco form " and soluble in water, in this state, therefore, a dye, although having the same basic chemical structure, the reactive group is modified.
Classification by origin
Colorants are divided according to their origin or their mode of production.
- Synthetic colorants are manufactured with chemical methods, for commercial quantities of natural industrially.
- Natural colorants are extracted directly from plants, animal parts, from earth or rock. Such are the inorganic white minerals, colorful earth pigments, mineral pigments and any natural colored organic substances such as saffron, indigo or purple real.
Special colors are colorants with special physical properties which change their color under the influence of physical and chemical variables.
- Temperature dependent: colorant having Thermochromism
- UV light: fluorescent colors
- Reacting by light impact dyes: photochromic dyes
- Indicator colors: be affected by acid -base reactions or redox processes and help identify chemical classes of substances to
- Pressure-sensitive colorants
- Coloring additives in pyrotechnics are mostly based on the spectral lines of the elements, see flare