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Dyes, also known as reactive dyes. When the fiber is dyed with a chemically reactive dyes. Such dye molecule contains a chemical reaction can occur with the fiber group, and fiber-reactive dye to form a covalent bond therebetween when the dye, as a whole, so that improved washing and rubbing fastness. Reactive dyes are a new class of dyes. 1956 Britain’s first production of the reactive dye Procion grades. Reactive dye molecule includes two main components and reactive dye precursor group capable of reacting with the fiber reactive group is called a group.
Reactive dyes (reaction dye), also known as reactive dyes. Molecules containing chemically reactive groups, in aqueous solution can be cotton, wool and other fiber-reactive dye forming common bonds. It has a high washing fastness
By radicals different reactive dyes are mainly divided into two categories.
Symmetrical three nitrogen benzene type having the general formula:
Where D is the parent dye. In such reactive dyes, reactive chloride atoms chemical properties more lively. Dyeing, chlorine atom in an alkaline medium is substituted cellulose fibers, a leaving group to leave. The reaction between the dye and the cellulose fibers belonging SN2 reaction (see substitution reaction).
Such vinylsulfone reactive dyes contained in the active group is sulfate vinyl sulfone (D-SO2CH = CH2) or β- glycolate sulfone group. Dyeing, β- hydroxyl ethyl sulfone sulfate in an alkaline medium to elimination reaction of vinyl sulfone group, and then close with cellulose fibrosis, by nucleophilic addition reaction to form a covalent bond.
These two types of reactive dyes is the world’s largest output current major reactive dyes. In order to improve the fixation rate of reactive dyes in recent years, the introduction of two active groups in the dye molecule, known as dual reactive dyes. Reactive dyes cellulose fibers in addition to the species, but also the development of protein fibers (such as silk, wool and other fibers) with varieties.For more information about dyes see our website:: www.cycolorant.com