Recent Advances in Disperse Dye Development and Applications By ALAN T. LEAVER, BRIAN GLOVER and PETER W. LEADBETTER, IC1 Colours. Manchester IJnited Kingdom olyester fiber production in the U.S. obvious needs. Firstly, there is a need for Poor wetfastness P fell markedly in 1990. Stapleproduc- new dyes to be tailored to satisfy shorter, 0 Expensive tion fell by 12.3% and filament production reproducible and more economical dyeing Environmental problems in manu- by 8.7% compared with 1989 (I). In 1991 processes. Secondly, with the increasing facture some recovery is expected as the country use of polyester and its blends in lei- Compared with many other dye types, comes out of recession with increases in surewear and sportswear, there is a clear anthraquinone disperse dyes are tinctori- consumer spending and housing pur- demand for dyes of higher wetfastness. ally weak. Furthermore, with the intro- chases. On a world basis, the forecasts are This requirement has been exacerbated by duction of detergents and multifiber strips much more optimistic. Latest estimates the introduction of fabrics based on poly- to evaluate wetfastness, they have been put the long term growth rates for polyes- ester microfibers where higher depths of found to have, in the main, poor wetfast- ter fiber at 5% per annum against 3% for all shade have to be dyed to obtain the same ness, being particularly poor with respect Ebers. The highest growth rates are pre- visual yield as conventional polyester. to staining adjacent nylon. For dye users dicted in Asia and the Far East where over Last, but by no means least, new disperse they are expensive relative to mono-azo 8% per annum is forecast for the period dye development has to be directed to- disperse dyes; for dye manufacturers they 1990-2000. Over the same period a growth wards minimizing pollution of the envi- are environmentally problematical. rate ofjust 0.5% per annum is predicted in ronment. Many key anthraquinone disperse dyes the U.S. These objectives are not mutally exclu- are derived from sulphonation of an- It is against this background ofa signifi- sive but interrelated, and all need to be thraquinone itself, which for most manu- cant global growth rate in polyester fiber taken into account in any dyedevelopment facturers requires the use of mercury that major dye manufacturers continue to program. catalysts. Hence, there has been a clear devote substantial resources to the devel- need to find replacements for anthraqui- for the Properties of Anthraquinone none dyes to counter these deficiencies. opment of new disperse dyes Disperse Dyes coloration of polyester and its blends, This does not mean that anthraquinone particularly with cellulose. Anthraquinone disperse dyes were devel- disperse dyes do not still have their place. Disperse dye development has to be oped more than 60 years ago for the They do. They are still seen as essential to directed towards satisfying a number of coloration of cellulose acetate. They were satisfy the lightfastness requirements for 2, subsequently found suitable for the color- automotive outlets. They are still used ation of other such synthetic fibers as extensively for such nonpolyester syn- nylon, cellulose triacetate and polyester. thetic fibers as acetate, triacetate and The commercial development of new It was the phenomenal growthof polyes- nylon, together with blends of these sub- disperse dyes for 100% polyester and ter fiber production during the 1950s and strates with polyester. Probablytheirmain polyester/cellulose blends is reviewed. 1960s that signaled an extensive research The deficiencies of traditional use today is in pale shade trichromatic anthraquinone disperse dyes for bright and development program for new dis- dyeing where their good coverage, good red and bright blue shades are perse dyes for polyester. Research was reproducibility and good leveling proper- highlighted from the standpoint of largely concentrated on substituted an- ties are still needed, and their obvious today's requirements for higher thraquinone and substituted benzenoid deficiencies of expense and poor wetfast- wetfastness and more economical mono-azo structures. ness can be largely discounted. processing. More acceptable alternative The anthraquinone disperse dyes devel- Some developments have continued. dyes are described with emphasis on oped over this period had some clear Japanese manufacturers have devised and exhaust dyeing of 100% polyester successfully operated mercury-free pro- microfibers and one-bath dyeing of benefits. polyester/cellulose blends. Some Brightness of shade (particularly cesses for anthraquinone intermediates. aspects aimed at reducing blues and reds) Ciba-Geigy has recently added a com- environmental pollution, namely Very good lightfastness pletely new anthraquinone disperse dye to alkali-clearable disperse dyes and choice Good level dyeing properties its range: Terasil Brilliant Blue FFL (C.I. of formulating agents, are discussed. 0 Good coverage properties Disperse Blue 361), a bright mid-blue of Good reproducibility high lightfastness. A further attraction of anthraquinone However, with few exceptions, recent KEY TERMS dyes was the fact that many gave good developments in disperse dyes have con- yields with carriers and enabled satisfac- centrated on other types of dye structures. tory dyeings to be achieved at the boil, in Many projects have been aimed at improv- Anthraquinone Dyes nonpressurized machinery at a time when ing on and replacing anthraquinone dis- Benzodifuranone Dyes atmospheric dyeing machines were more perse dyes and satisfying demands for the Disperse Dyes common. highest quality performance. Polyester/Cellulose During the past 20 years, however, the Polyester Fibers following deficiencies of anthraquinone Replacements for Anthraquinone Polyester Microfibers disperse dyes have come forward. Disperse Dyes Tinctorially weak 0 Bright Blues. In thelate 1960sand early 18 Cco Vol. 24, No. 1 1970s bright blue mono-azo disperse dyes conjugated double bonds it possesses.4-n. started to appear and be offered as poten- Table 1. Comparison of Nylon obvious approach was to try to synthesize Staining: C.I. Disperse Blue, 165 vs. new molecules similar in structure to tial replacements for anthraquinone dis- C.I. Disperse Blue 56 perse dyes. Typical of these dyes was I 1 anthraquinone dyes but containing an C.I. Disperse Blue 165 (Fig. 1). This increased number of conjugated double dye possesses a significant improvement Disperse Dye IS0 105 bonds. in tinctorial strength, being more than Preparations’ C06.CE Wash Test A search of the literature revealed that three times stronger than the popular Pb NC Junek (2) in 1960 had reported the forma- anthraquinone C.I. Disperse Blue 56 C.I. Disperse Blue 56 4 2-3 tion of a novel red lin-pentacenequinone ‘2.1. Disperse Blue 165 4 4 (Fig. 2). - from the reduction of benzoquinone with As shown in Table 1, the wetfastness of aDyes were applied at 1/1 standard depth cyanoacetic acid. Greenhalgh (3),at ICI, the dye was also superior when subjected and heatset for 30 seconds at 180C. bP = stain repeated this work but could not confirm to the IS0 105 C06/C2 washfastness test, on polyester. CN = stain on nylon. the reported structure. After extensive with much lower staining of nylon adja- analysis and spectroscopic studies, the cent fabric. superior to other azo blues in its resistance dihydroxybenzodifuranone structure was However, while the deficiencies of low todecomposition during high temperature proposed and confirmed as correct. This tinctorial strength, low wetfastness and dyeing. Its reproducibility is of the same particular dye was very dull bluish red and cost ineffectiveness had been largely over- order as C.1. Disperse Blue 56 and with its of no commerical value. But as a new come, the new mono-azo dye was more superior heatfastness and wetfastness, and chromogenic system, it was of great signif- easily reduced during a high temperature good cotton reserve, it is ideally suited for icance. dyeing cycle and as a consequence was less batchwise dyeing, continuous dyeing and reproducible, particularly in tertiary Commerical Development printing of 100% polyester and polyester/ Of Benzodifuranone Dyes shades. The dye found great acceptance in cotton blends. It is being marketed as continuous dyeing outlets on polyester/ Dispersol Blue C-RN 200 Grains. IC1 has since developed two very bright cellulose blends owing to its higher heat 0 Bright Reds. A very similar line of red dyes based on benzodifuranone chem- and wetfastness, but in batchwisedyeing it development has been followed in the istry-Dispersol Red C-BN and Dispersol has been only moderately successful. replacement of the popular bright bluish- Brilliant Scarlet D-SF. Both are being The shade of C.I. Disperse Blue 165 is red anthraquinone dye, C.I. Disperse Red marketed in solid and liquid forms for also considerably greener than C.I. Dis- 60 (Fig. 4). Like the anthraquinone blue, it exhaust and continuous dyeing outlets. perse Blue 56. On shade grounds alone, it is still widely used in pale tertiary shades The same two dyes have also been specially could not convincingly be offered as a owing to its excellent reproducibility. But formulated for use in discharge printing of viable alternative. This last objection has for medium to heavy shades it has been 100% polyester and polyester/cellulose been largely overcome in the last two to largely replaced by the introduction in the blends as Dispersol Red BN PC Liquid three years by the development of a new late 1970s of the mono-azo Bayer dye, and Dispersol Brilliant Scarlet SF PC dye with a closely related structure, C.I. Resolin Red F3BS (C.I. Disperse Red Liquid, making a total of six sales products Disperse Blue 366 (Fig. 3). 343). This dye has superior heatfastness in all. It is also planned to extend the range This dye is very much redder than C.I. and wetfastness compared with an- of benzodifuranone dyes to other shade Disperse Blue 56 but mixtures containing thraquinonedye, and tinctorially it is more areas.