Monoazo metal complex dyes utilising heterocyclic coupling components - recent developments

摘要

The first use of metal-complex dyes can be traced to the Middle Ages in the process of mordant dyeing. In this process the textile fabrics to be dyed are impregnated with a solution of salts of a metal such as aluminium, iron, chromium or tin and then treated with a naturally occurring colorant capable of chelation to achieve metallisation within the fibre. The so called after chrome method was developed in the late 1940s and gained commercial importance in the coloration of the wool in heavy shades. Two other chrome methods, namely the mordant chrome and the metachrome techniques were employed. Mordant chrome is a variation of the mordant dyeing process. In the metachrome method the dyeing and chroming are performed in a single bath containing the dye, sodium dichromate, and ammonium sulphate. Besides these premetallised dyes became commercially important.