S.M. Burkinshaw

Chemical principles of synthetic fibre dyeing

1. Polyester.- 1.1. Introduction.- 1.2. Disperse dyes.- 1.2.1. Aqueous phase transfer.- 1.2.2. Thermodynamics of dyeing.- 1.2.3. Kinetics of dyeing.- 1.2.4. Effect of crystal form of the dye on dye adsorption.- 1.2.5. Effect of particle size and distribution on dye adsorption.- 1.2.6. Effect of dispersing agents on dye adsorption.- 1.2.7. Effect of levelling agents on dye adsorption.- 1.2.8. Effect of temperature on dye adsorption.- 1.2.9. Isomorphism.- 1.2.10. Oligomers.- 1.2.11. Carrier dyeing.- 1.2.12. Solvent-assisted dyeing.- 1.2.13. Solvent dyeing.- 1.2.14. High-temperature dyeing.- 1.2.15. Thermofixation.- 1.2.16. Afterclearing.- 1.3. Azoic colorants.- 1.4. Vat dyes.- References.- 2. Nylon.- 2.1. Introduction.- 2.2. Anionic dyes.- 2.2.1. Barre effects.- 2.2.2. Acid dyes.- 2.2.3. Mordant dyes.- 2.2.4. Direct dyes.- 2.2.5. Reactive dyes.- 2.3. Cationic dyes.- 2.4. Non-ionic dyes.- 2.4.1. Disperse dyes.- 2.4.2. Disperse reactive dyes.- 2.4.3. Azoic colorants.- 2.4.4. Vat dyes.- References.- 3. Acrylic.- 3.1. Introduction.- 3.2. Cationic dyes.- 3.2.1. Thermodynamics of dye adsorption.- 3.2.2. Kinetics of dye adsorption.- 3.2.3. Effect of pH on dye adsorption.- 3.2.4. Effect of electrolyte on dye adsorption.- 3.2.5. Effect of temperature on dye adsorption.- 3.2.6. Effect of water on PAN fibres.- 3.2.7. Carrier dyeing.- 3.2.8. Retarding agents.- 3.2.9. Dye-fibre characteristics.- 3.2.10. Migrating cationic dyes.- 3.2.11. Gel dyeing.- 3.3. Disperse dyes.- 3.3.1. Thermodynamics of dyeing.- 3.3.2. Kinetics of dyeing.- 3.3.3. General considerations.- References.- 4. Microfibres.- 4.1. Introduction.- 4.1.1. General considerations.- 4.1.2. Microfibre production.- 4.2. Polyester microfibres.- 4.2.1. Mass-reduced polyester fibres.- 4.3. Polyamide micro fibres.- References.- Dye Index.

The use of dendrimers to modify the dyeing behaviour of reactive dyes on cotton

Cotton fabric which had been pretreated with a dendrimer displayed markedly enhanced colour strength with reactive dyes, even when dyeing had been carried out in the absence of both electrolyte and alkali. Competitive dyeing of untreated and dendrimer pretreated cotton suggests that the dendrimers offer the potential for differential-dyeing patterning possibilities. When non-competitively dyed, dendrimer pretreatment also enhances colour strength.

A greener approach to cotton dyeings with excellent wash fastness

Attempts were made to find a more environmentally friendly method of dyeing cotton as an alternative to standard reactive dyeing processes that require high levels of water, salt and alkali and produce high levels of effluent contamination. It was intended that the new method would not compromise the excellent wash fastness levels typical of reactive dyed cotton. By employing a pre-treatment method, salt and alkali could be completely eliminated from the dyeing process and, in comparison with standard reactive dyeing processes, the time taken for the dyeing process to be completed could be significantly reduced and the volume of water required could be halved. The dyeings secured using the pre-treatment method had wash fastness values equal to those observed for the standard reactive dyeings.

The dyeing of conventional and microfibre nylon 6.6 with reactive disperse dyes

Abstract The dyeing and wash-fastness characteristics of three monoazo reactive disperse dyes and one monoazo disperse dye on both conventional and microfibre Nylon 6.6 have been examined. Application at 95° C and pH 8 yielded optimum colour strength for the reactive disperse dyes on both types of fibre. The presence of a commercial dispersing agent in the dyebath enhanced the levelness, but did not markedly reduce the colour strength of dyeings achieved using each of the three reactive disperse dyes on both conventional and microfibre Nylon 6.6. The excellent build-up profiles obtained for the three reactive disperse dyes were in sharp contrast to the poor build-up profile secured for the disperse dye on both substrates; this was attributed to the covalent reaction of the reactive disperse dyes having promoted dye uptake. The three reactive disperse dyes exhibited excellent wash-fastness on both conventional and microfibre Nylon 6.6, the level of fastness achieved being identical on both types of fibre.

Capillary zone electrophoresis in the analysis of dyes and other compounds employed in the dye-manufacturing and dye-using industries

High resolution separation of several dyes and related intermediates, as well as other compounds employed in the dye-manufacturing and dye-using industries, has been achieved using capillary zone electrophoresis (CZE). The analysis of anionic dyes and some non-coloured anionic intermediates has been achieved using 10 mM Na2B4O7−40 mM sodium dodecyl sulphate (SDS) buffer; high-resolution separations of water soluble anionic, neutral and cationic intermediates were also achieved using this micellar buffer. Micellar electrokinetic capillary chromatography (MECC) has also been developed for the analysis of aqueous insoluble, electrically neutral compounds by incorporating a co-solvent, acetonitrile, into a micellar buffer. In addition, MECC has been used successfully for following all the major steps involved in the synthesis of a disperse dye.

Pretreatment of cotton to enhance its dyeability; Part 2. Direct dyes

Abstract Three commercial cationic fixing agents, namely Matexil FC-PN (ICI), Matexil FC-ER (ICI) and Solfix E (Ciba), originally marketed as aftertreating agents for direct dyes, were used as pretreatments for cotton modification. Pretreated cotton was dyed with four direct dyes and the effect of pretreatment on the colour strength as well as the wash and the light fastness of the dyeings were investigated. The dyeings were also aftertreated with the same agents used for the pretreatment, and their wash fastness properties were compared with those of the aftertreated standard dyeings. Pretreatment was found to increase the colour strength of the dyeings when dyeing had been carried out without electrolyte. However, when electrolyte was used, the pretreated samples exhibited generally lower colour strength than the standard dyeings. The wash fastness of the dyeings was almost unaffected by pretreatment while light fastness was slightly lowered.

The dyeing of conventional and microfibre nylon 6,6 with reactive dyes—3. Vinyl sulphone and chlorotriazine dyes

The dyeing behaviour and wash fastness of three vinyl sulphone and five chlorotriazine dyes on conventional decitex and microfibre Nylon 6,6 fabrics were examined; the extent of dye fixation was determined by stripping unfixed dye from the dyeings using aqueous pyridine.

Improvement of the wash fastness of non-metallised acid dyes on conventional and microfibre nylon 6,6

Abstract The adsorption of a commercial syntan on to both conventional and microfibre nylon 6,6 was found to increase with decreasing application pH, indicating that ion-ion interaction contributes to syntan-fibre substantivity. Uptake of the syntan on both types of fibre increased with decreasing liquor ratio, possibly as a result of syntan aggregation, and also increased with increasing application temperature, this being attributable to the higher kinetic energy of the syntan molecules and the greater extent of fibre swelling operative at the higher temperatures. From the finding that uptake of the synthetic tanning agent on to undyed conventional and microfibre nylon 6,6 followed a BET mechanism, it was postulated that adsorption involves the formation of multi-layers and that forces other than ion-ion contribute towards syntan-fibre interaction. This postulate gained support from the observation that although the presence of 1% omf dye on the two types of fibre reduced the extent of syntan uptake, the mechanism of syntan adsorption on to both substrates was unaffected. The finding that syntan uptake was greater on microfibres than conventional fibres was attributed to the greater surface area of microfibres. Despite the greater uptake of the syntan on to dyed microfibre, the wash fastness of syntanned, dyed microfibre was lower than that of its syntanned, dyed conventional decitex counterpart. The effectiveness of the syntan in improving the wash fastness of several non-metallised acid dyes on microfibre was enhanced by the subsequent application, to the syntanned, dyed substrate, of certain cationic agents. The level of wash fastness achieved using this syntan/cationic agent system was considerably higher than that obtained using an aftertreatment with either 4% omf syntan or the full backtan.

The dyeing of conventional decitex and microfibre nylon 6,6 with reactive dyes-I. Chlorodifluoropyrimidinyl dyes

Conventional decitex and microfibre nylon 6,6 fabrics were dyed using three commercial chlorodifluoropyrimidinyl reactive dyes. Weakly acidic conditions (pH 4) were found to yield optimum colour yield and level dyeings were obtained without the need for electrolyte or a proprietary levelling agent. The three dyes displayed good build-up on both conventional decitex and microfibre nylon 6,6 fabrics; generally, dye build-up was similar on both types of fabric at low depths of shade but was greater on conventional fabric at high depths of shade. The fastness of the washed-off dyeings to the ISO C06/C2 wash test, at each of seven depths of shade (0.1%, 0.5%, 1%, 2%, 3%, 4% and 5% omf), was very good. Treatment of the dyeings before wash-off with a commercial syntan reduced the amount of dye removed during wash-off but altered the colour of the dyeings. Generally, syntan treatment did not improve the wash fastness of the dyeings.

A study of the wash-off and aftertreatment of dichlorotriazinyl reactive dyes on cotton

Abstract Five commercial dichlorotriazinyl reactive dyes, applied at 1, 2 and 4% omf to cotton fabric, were washed-off using four water-based methods and one detergent-based method; the washed-off dyeings were then subjected to the ISOC06/C2 wash fastness test. None of the four water-based wash-off methods used resulted in the dyeings achieving a level of fastness that was as high as that achieved using the detergent-based wash-off method. The fastness to washing of the dyeings which had been washed-off using the four water-based methods was improved using an aftertreatment involving two proprietary cationic fixing agents. The extent of improvement in wash fastness imparted by each fixing agent increased with increasing severity (temperature) of the wash-off method. In the case of dyeings that had been washed-off using water at 80°C and 98°C, aftertreatment with the two cationic fixing agents resulted in wash fastness ratings that were either identical to, or only one-half point lower than, comparable depth dyeings which had been washed-off using detergent. The colour strength of the washed dyeings that had been washed-off using water and aftertreated with the two cationic fixing agents was greater than that of comparable depth, washed dyeings that had been washed-off using detergent.