Aminofluorotriazine-sulphatoethylsulphone Dyes

Early in 1988 Ciba-Geigy launched the Cibacron C range of mixed bifunctional dyes. They contain a new aliphatic vinylsulphone system and either a monofluorotriazine bridging group (Figure 1) or an arylvinylsulphone function [1]. They are designed mainly for pad applications and appear to be characterised by medium to low affinity, good build-up, easy wash-off and high fixation. Their outstanding bath stability and high fixation make them especially suitable for pad–batch dyeing [2]. The manufacturing cost of these structures is believed to be relatively high but the purchase cost to the dyer may be offset by enhanced cost-effectiveness in use attributable to efficient fixation and easy wash-off, possibly the best approach so far towards environmentally acceptable reactive dyes [3].

An important feature of the Sumifix Supra (NSK) type of bifunctional system (Figure 2) is the major difference in reactivities between the amino- chlorotriazine moiety and the much more reactive vinylsulphone group.

There are some practical conditions, notably in pad–batch application, that do not allow full advantage to be taken of both types of reactive group present. The combination of aminofluorotriazine and vinylsulphone in the Cibacron C (CGY) system, both groups offering effective fixation under  virtually the same conditions, exploits the concept of bifunctionality more effectively.

These factors have been demonstrated elegantly in a detailed evaluation by pad–batch dyeing of cotton with three commercially important copper formazan reactive dyes:

1. Cibacron Blue F-R (CI Reactive Blue 182) with a monofunctional 2-fluoro- 4-sulphoanilinotriazine system.
2. Sumifix Supra Blue BRF (CI Reactive Blue 221) with a mixed bifunctional 2-chloro-4-vinylsulphonylanilinotriazine system.
3. Cibacron Blue C-R with a synchronised bifunctional 2-fluoro-4-vinylsulphonylalkylaminotriazine system.

Under the relatively mild conditions of pad–batch fixation within 6 h batching time, the mixed bifunctional system behaved more like a monofunctional vinylsulphone dye and only the synchronised Cibacron C (CGY) system showed truly bifunctional performance [4].

Reference:

1. J P Luttringer and A Tzikas, Textilveredlung, 25 (1990) 311.
2. J M Sire and P Browne, Melliand Textilber., 72 (1991) 465.
3. A H M Renfrew and J A Taylor, Rev. Prog. Coloration, 20 (1990) 1.
4. P Scheibli and S Koller, Proceedings of the Conference on Reactive Dyes, Leeds University, Leeds (Sep 1989).