Dyestuffs
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Acid Dyes
Acid dyes are anionic, soluble in water and are essentially applied from acidic bath. These dyes possess acidic groups, such as SO3H and COOH and are applied on wool, silk and nylon when ionic bond is established between protonated –NH2 group of fibre and acid group of dye.
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Optical Dyes
Features Optical brighteners are synthetic chemicals which are added to the liquid and detergent powder to make clothing appear whiter, brighter and cleaner. They are the modern day replacements for the decades old method of bluing adding small amounts of blue dye to fabric to make it appear whiter. Details Optical Brightener Agent Product Catalog -
Solvent dyes
A solvent dye is a dye which is soluble in organic solvents and is frequently used as a solution in those solvents. This category of dyes is used to color items such as waxes, lubricants, plastics, and other hydrocarbon-based nonpolar materials. Any dyes used in fuels, for example, would be considered solvent dyes and they are not soluble in water.
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Disperse dyes
Disperse dye is one kind of organic substance which is free from ionizing group. It is less soluble in water and used for dyeing synthetic textile materials. Disperse dyes achieve their best results when the dying process takes place at high temperatures. Specifically, solutions around 120°C to 130°C enable disperse dyes to perform at their optimal levels.
Hermeta provides disperse dyes with various techniques for colouring synthetics such as polyester, nylon, cellulose acetate, vilene, synthetic velvets and PVC. Their effect is less potent on polyester, due to the molecular structure, allowing only pastel through to medium shades, however full colour can be achieved when heat transfer printing with disperse dyes. Disperse dyes are also used for the sublimation printing of synthetic fibers and are colorants used in the manufacture of “iron-on” transfer crayons and inks. They can also be used in resins and plastics for surface and general coloring uses.
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Metal Complex Dyes
Metal complex dye are a family of dyes that contain metals coordinated to the organic portion. Many azo dyes, especially those derived from naphthols, form metal complexes by complexation of one of the azo nitrogen centers. Metal complex dyes are premetallised dyes that show great affinity towards protein fibers. In this dye one or two dye molecules are coordinated with a metal ion. The dye molecule is typically a monoazo structure containing additional groups such as hydroxyl, carboxyl or amino, which are capable of forming a strong co-ordination complexes with transition metal ions such as chromium, cobalt, nickel and copper.
