Imperial Chemical Industries: ‘Procion’ Reactive Dyes

Abstract

An ideal dye system should offer a full range of shades at an economic price, be easy to use and be ‘fast’, that is, not fade under adverse conditions such as sunlight and washing. For cellulosic fibres such as cotton, ease of use implies that dyeing should be done in aqueous solution. Fastness is achieved by attaching the coloured substance to the fibres in such a way as to resist its subsequent removal. Conventional dyes rely on physical links resulting from processes such as the absorption of the dye by the fibre and subsequent treatment to render it insoluble. The innovation was to produce a dye which would react chemically with the fibre. The resulting covalent bond provided a strong link easily capable of giving moderate-to-high fastness during washing over a full shade range for the first time.