Dye types

Description

Draft

TABLE 1 : Dye Classification Based on Application Method

Application Method	Description	Substrates	Some chemical groups	Examples
Acid Dyes	A large class of dyes containing one or more acidic end groups (sulfonic, phenolic, carboxylic, etc.) that react with the basic end groups found in amides to form a uniform, lightfast color. Acid dyes are rarely used on cellulose.	wool, silk, mohair, angora, cashmere, nylon, paper, leather, inks	azo, anthraquinone, azine, nitro, nitroso, triphenylmethane, xanthene	Acid Red, Coomassie Blue
Basic Dyes	A class of water-soluble synthetic dyes containing a cationic functional group, such as an amide. Basic dyes produce bright colors with poor colorfastness that can be improved by the use of mordants.	paper, acrylic, modified nylon, polyester, ink	azo, azine, acridine, cyanine, diphenylmethane, oxazine, thiazine, triarylmethane,	Methylene blue, Crystal violet, Malachite green, Rhodamine
Direct Dyes (Substantive Dyes)	Water-soluble dyes that quickly adhere to fibers without the aid of a mordant. Direct dyes were primarily used for dying cellulose. The group includes both natural synthetic dyes. Because direct dyes generally possess poor colorfastness, some after-treatments, such as diazotization development, are used to improve washfastness.	cotton, rayon, linen, paper, leather, nylon	azo, dioxazine, phthalocyanine, stilbene, as well as some natural dyes	henna, saffron, turmeric, Congo red, Brilliant blue, Fast yellow RSC
Disperse Dyes	Non-ionic, water-insoluble dye particles tapplied in a water-dispersion using a surfactant along with high-temperature (100-130C) and/or pressure to incorporate the colorant into a synthetic fiber. They provide good lightfastness and washfastness. Also used for heat-transfer printing.	polyester, acetate, acrylic, nylon, polyester-cotton blends, polyamide, plastics	azo, anthraquinone, styrol, nitroarylamine, benzodifuranone	Disperse Blue 56
Mordant Dyes	Dyes that require a mordant to improve the fastness of the dye against water, light and perspiration. The mordant choice can change the final color significantly. Most natural dyes are mordant ( with alum) dyes and the most synthetic mordant (with chrome) dyes are used for wool (usually black and navy shades). The mordant is may be applied before or after treatment.	wool, leather, anodized aluminum	azo, anthraquinone, most natural dyes (madder, cochineal, weld, fustic, etc)	Synthetic alizarin, Cochineal scarlet
Reactive Dyes	Dyes for which a reactive chromophore forms covalent connections with functional groups (cellulose, hydroxyl or amino) on the fiber under the influence of heat or pH. The dyes are vibrant, permanent, wash-fast color. It is the top choice for home dyeing.	wool, silk, nylon, cotton, linen, rayon, viscose, bamboo, hemp, acrylic, acetate	azo, anthraquinone, phthalocyanine, oxazine, formazan, basic	Procion MX , Remazol, Cibacron, Drimarene
Solvent Dyes (Oil-based Dyes)	Non-polar organic dye that is soluble in organic solvents (alcohols, esters, ketones), oils and other hydrocarbons. It is water-insoluble. Creates transparent shades that typically have good lightfastness	plastics, gasoline, varnishes, lacquers, stains, inks, fats, oils, waxes	azo, anthraquinone, triphenyl methane, phthalocyanine	Solvent Red 26, Solvent Green 3, Solvent Blue 35
Sulfur Dyes	A two-part dye used to dye cellulose with dark color. The initial alkaline reduction bath with sodium sulfide produces a pale yellow-green color that oxidized to produce a dark black color. Environmental concerns, possible fiber degradation	cotton, linen, rayon,	sulfide, disulfide, thiazole	Sulfur Black, Indophenol
Vat Dyes	A multi-step process in which water-insoluble dyes are made soluble via a chemical reduction process often in hot water, The fibers are dyed, then an oxidation process (such as air drying) is used to redevelop the water-insoluble color. Known for excellent colorfastness (both light and wash) though color ranges are limited and often dull.	cotton (especially Denim), acetate	anthraquinone and indigoids	Indigo, Alizarin Yellow

TABLE 2 : Dye Classification Based on Chemical Structure

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