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Acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber.
The production and improvement of colorants was a driver of the early synthetic chemical industry, in fact many of today's largest chemical producers started as dye-works in the late 19th or early 20th centuries, including Bayer AG(1863). [2]
An acid dye is a dye that is typically applied to a textile at low pH. They are mainly used to dye wool, not cotton fabrics. [1] Some acid dyes are used as food colorants, [2] [3] and some can also be used to stain organelles in the medical field. Acid dyes are anionic, soluble in water and are essentially applied from acidic bath.
Mordants are chemical agents which have power of making dyes to stain materials which otherwise are unstainable Mordants are classified into two categories: a) Basic mordant: React with acidic dyes e.g. alum, ferrous sulfate, cetylpyridinium chloride etc. b) Acidic mordant : React with basic dyes e.g. picric acid, tannic acid etc.
Some classes include disperse dyes, metal-complex dyes, reactive dyes, and substantive dyes. Also called direct dyes, substantive dyes are employed for cellulose-based textiles, which includes cotton. The dyes bind to the textile by non-electrostatic forces. In another classification, azo dyes can be classified according to the number of azo ...
Dyeing is normally done in a special solution containing dyes and particular chemical material. Dye molecules are fixed to the fiber by absorption, diffusion, or bonding with temperature and time being key controlling factors. The bond between the dye molecule and fiber may be strong or weak, depending on the dye used.
Basic dye 11050 azo 2869-83-2: Juglone: Oil red BS Black walnut Natural brown 7 75500 natural 481-39-0: Kaempferol: Rhamnolutein Natural yellow 13 75640 natural 520-18-3: Kermes: Kermesic acid: Natural red 3 75460 natural 18499-92-8: Lac: Shellac Laccaic acid Xanthokermesic acid Natural red 25 75450 natural 60687-93-6: Lanosol yellow 4G ...
Substantive dyes work best on textiles with high contents of cellulose, such as cotton. In contrast to direct dyes, wool and leather goods are dyed by the process of ion exchange, exploiting the cationic nature of proteins near neutral pH. The development of substantive dyes helped make mordant dyes obsolete. [2]