Organic molecules are used to manufacture synthetic dyes. Before that, the dyes were made from natural products like flowers, roots, vegetables, and other such things. But the problem was that the natural dyes were never of the same hue and intensity. The synthetic dyestuffs can be made with consistency and produce the same hue and color. Sodium nitrite manufacturer provides the required raw material to produce these dyes. With the use of computer color matching, colors produced a match from one batch to the other.
Discovery
A chemist was searching for a cure for malaria, quinine, but discovered the first synthetic dye accidentally. The oxidation of the aniline could color the silk, and from the coal tar derivative, he made the reddish-purple dye. The color was called mauve. The dye wasn’t stable to sunlight or water and faded quickly. The discovery resulted in more research with coal tar derivatives and other organic compounds. In this way, the entire new industry of the synthetic dyes came into existence. Today these synthetic dyes are less expensive, have colorfastness, and dominate the industry as compared to the natural dyes. Thousands of distinct dyes are manufactured in the world.
How are Dyes classified?
They are classified by their chemical composition, types of fibers to which they can be applied, by their hue, or the method of application. The dye molecules attach to the surface of the fiber, absorbed by the fiber, interact with the fiber molecules. Each fiber reacts differently to the dyes. Fiber modifications also respond differently to the same dye. With a dye classification, different hues have different colorfastness.
Acid-Based Dyes
These are readily soluble in water and can be applied to silk, nylon, modified rayon, certain modified acrylic, and polyester fibers. Those fibers can be damaged by acids like the cellulosic, should not be dyed with this family of the dyes. The dyes in this class vary significantly in their composition, but most of them used the acid bath. These dyes produce bright colors. They come in complete color range, but the colorfastness may vary.
Naphthol Based Dyes
These dyes are produced within the fiber of cellulose fibers. The fiber is rinsed with one component of the dye, followed by the treatment with the other component. In this way, the dyes are formed. These two components join under the suitable condition (using the low-temperature bath) a large, insoluble colored molecule forms inside the fiber. As the color is within the fiber, colorfastness is excellent. Excess color on the outside of the fiber rubs off even if it is not removed.
Cationic Dyes
These dyes are very bright but don’t have a high quality of colorfastness. They have limited use on the cellulosic and protein fibers. Wool and silk can be dyed by the basic dyes in the dye bath, which contains the acid. The cotton fibers can be dyed by the basic dyes but only in the presence of mordant or metallic salt. Basic dyes are relatively colorfast when used on the acrylic fibers. Nylon and polyester fibers have been modified to accept the basic dyes and exhibit excellent colorfastness.
Substantive Dyes
These are soluble and have an affinity for the cellulose fibers. An electrolyte, salt is added to the dye by the fiber. The dye is absorbed by the fiber. Colorfastness to the light is excellent but not to the laundering.
Finally,
Reach out to the sodium nitrite manufacturer who provide the chemical to produce the dyes. Each dye comes with its colorfastness and specific use depending on the fiber. Colorfastness varies accordingly.
