Abstract


Some new acid dyes have been synthesized by coupling tetrazotised 4, 4-methylene-bis (2, 5-dimethyl aniline) (2) with different coupling components (3a-f) and their dyeing performance on wool, silk and nylon have been assessed. They are characterized by their elemental analysis, UV-visible spectra, IR and PMR spectra. All the dyes showed good exhaustion and fixation properties. All the dyes show generally moderate to very good light fastness properties. The washing and rubbing fastness properties ranges from good to excellent fastness on wool and silk and nylon.


Keywords


4,4-methylene-bis(2,5-dimethyl aniline), Exhaustion, Fixation, Light Fastness, Wash Fastness and Rubbing Fastness.


Introduction


Acid dyes are water-soluble anionic dyes that are applied to nitrogeneous fibres such as wool, silk, nylon and modified acrylic fibres from acid or neutral baths. Attachment to the fibre is attributed atleast partly to salt formation between anionic groups in the dyes and cationic groups in the fibre. Acid dyes are not substantive to cellulosic fibres. The acid dyes were probably originally so named because of the presence of one or more sulphonic acid or other acidic groups in their molecules. The term applies to an application class rather than a chemical class however, and since acidic groups are also present in many mordant, direct and reactive dyes their presence is not a distinguish feature.


Acid dyes can easily be applied on wool, silk and other protein and polyamide fibres and therefore are largely used. They are applied generally in the presence of an organic or an inorganic acid and hence are called acid dyes. Acid dyes, the newest addition of existing dyes are the centre of attraction in dyestuff research1. Acid dyes have found wide application in dyeing wool, polyamide fibers and blends of both these fibers but they have to meet very high requirements as regards their application and fastness



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The Authors are associated with Department of Chemistry, Veer Narmad South Gujarat University,Udhana-Magdalla road, Surat, Gujarat, India.