什麼是染料

能使其他材料着色的有強烈色彩的複雜有機化合物，用於使紡織品、紙張、皮革和許多其他物質着色。在染色過程中，染料分子由溶液中沈積在材料上，且隨後不會被原來溶解它們的溶劑除去。古人所知的主要染料是由茜草屬植物和能產生靛藍的植物或軟體動物製得，現在一般由煤焦油和石油化工產品合成製得。第一種合成染料苯胺紫是1856年英國化學家珀金（W. H. Perkin）發明的，是一種煤焦油衍生物反應的意外產物，結果在19世紀末葉興起了大規模的煤焦油染料工業。染料分子的化學結構已證明易於改動，於是可製得範圍廣泛的煤焦油染料。化學合成的發展導致生產出許多新染料，可牢固地着色在許多不同類型的物質上。染料工業的一個重大進步，是發展了與纖維反應型染料，這種染料分子與它着色的纖維之間形成共價鍵，是將染料分子附着在纖維上的最牢固的方法。對於棉、毛、絲等天然材料，必須合成適合這些材料的獨特化學結構的染料。另一方面，也可以改變合成纖維的化學結構，以改變它們的染色性能。亦請參閲azo dye。

dye

Any of a class of complex organic compounds that are intensely colored, used to color textiles, leather, paper, and other materials. Major dyes known to the ancients came from plants such as indigo and madder (see madder family) or from the shells of mollusks; today most dyes are made from coal tar and petrochemicals. The chemical structure of dyes is relatively easy to modify, so many new colors and types of dyes have been synthesized. Dye molecules are deposited from solution onto materials in such a way that they cannot be removed by the original solvent. Fiber-reactive dyes form a covalent bond with the fiber. Other dyes require previous application of a mordant, an inorganic material that causes the dye to precipitate as an insoluble salt, or vat dyeing, in which a soluble colorless compound is absorbed by the fibers, then oxidized (see oxidation-reduction) to the insoluble colored compound, making it remarkably fast to washing, light, and chemicals. See also azo dye.