Dyeing of nylon 6 fabric with a bifunctional sulphatoethylsulphone reactive disperse dye

A bifunctional reactive disperse dye containing two temporarily anionic sulphatoethylsulphone groups was synthesised and applied to nylon 6 fabric by exhaust dyeing at a variety of pH levels and temperatures. A monofunctional reactive disperse dye containing one temporarily anionic sulphatoethylsulphone group was also synthesised, and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and total fixation yield under alkaline conditions. The results also indicate that the introduction of two temporarily anionic sulphatoethylsulphone groups of the bifunctional dye gave an enhancement in dyeing performance compared with that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Dyeing of nylon 6 fabric with a new bifunctional vinyl sulphone reactive disperse dye

A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.     

Levelling properties of some reactive dyes on cellulose

The levelling properties of nine reactive dyes containing one or two sulphatoethylsulphone reactive groups or one sulphatoethylsulphone and one monochlorotriazine reactive groups have been investigated. A novel test method specifically applicable to reactive dyes has been used in order to evaluate levelling. Undyed and dyed cotton samples were simultaneously dyed in the same bath and the fractions of the additional dye fixed on each of the cotton samples were determined afterwards. A dye distribution index has been proposed that predicts reactive dye levelling according to whether the index exceeds 50% or not. The index was found to depend not only on the nature of the dyes, but also on the concentration of the dye fixed on cotton, the dyeing temperature and the salt concentration in the dye liquor. In redyeing tests the degrees of primary and secondary exhaustion and of dye fixation were measured as a function of concentration of the dye fixed on cotton. Finally a satisfactory correlation was found between the index and the classical inorganicity/organicity value of the dyes. The results also suggest that the levelling properties depend on the degree of dye aggregation.     

Structure—reactivity studies of a new polyfunctional disulphide bis(ES-MCT/SES) reactive dye applied to silk

A new polyfunctional reactive dye containing disulphidebis(ethylsulphone-monochlorotriazine/sulphatoethylsulphone) reactive system has been synthesised and applied to silk. High exhaustion/fixation results have been achieved at 90 °C and pH 9. The vinylsulphone precursor of the disulphidebis(ethylsulphone) group combined with a sulphatoethylsulphone/monochlorotriazine reactive system confers a relatively high fixation efficiency for this type of polyfunctional reactive dye when compared with that of a conventional bifunctional reactive dye containing the sulphatoethylsulphone/monochlorotriazine reactive system. The results also indicate that high fastness properties were obtained for the reactive dyes under investigation.     

Synthesis and application of a polyfunctional bis(monochlorotriazine/sulphatoethylsulphone) reactive dye

The behavior of a polyfunctional reactive dye containing bis(monochlorotriazine/sulphatoethylsulphone) reactive system on silk has been investigated. The twinned monochlorotriazine/sulphatoethylsulphone reactive system confers a relatively high fixation efficiency of this type of polyfunctional reactive dye even at low salt and/or temperature conditions when compared with that of the conventional bifunctional reactive dye containing one monochlorotriazine/sulphatoethylsulphone reactive system. The results also indicate that the fastness properties are approximately the same for both the reactive dyes under investigation.     

Dyeing cotton with reactive dyes under neutral conditions

This paper describes a new method to dye cotton with selected reactive dyes by long-liquor – or so-called 'exhaustion'– processes under neutral conditions. Particularly promising results were obtained with reactive dyes containing free vinyl sulphone residues. Although there are dyes on the market that contain free vinyl sulphone groups, for example, the Novacron C (Huntsman) range of dyes, many of this class contain 'blocked' vinyl sulphone residues; examples include sulphatoethylsulphone or chloroethylsulphone precursor groups, and these may be preactivated to the highly reactive vinyl sulphone form simply by a mild alkali treatment. After this activation, neutral, long-liquor dyeings can be carried out at the boil in the presence of electrolyte. This new dyeing method gave very good results in terms of overall fixation efficiency values, without the need for alkali additions.     

Neutral dyeing of wool and wool/polyester blend fabrics using sulphatoethylsulphone reactive‐disperse dyes

Two models of temporarily anionic sulphatoethylsulphone reactive disperse dyes were applied to wool, polyester and wool/polyester blend fabrics at different dyeing pH. Maximum exhaustion values and colour yield were observed at pH 7. The results showed that reactive disperse dyes containing bis‐sulphatoethylsulphone reactive groups were more convenient for neutral dyeing of wool and wool/polyester blend fabrics if compared with a dye containing a mono‐sulphatoethylsulphone group. Excellent to very good wet fastness properties on all dyed fabrics were achieved.     

Synthesis and application of a hetero-bifunctional disulphidebis(ethylsulphone/monochlorotriazine) reactive dye

The behaviour of a heterobifunctional reactive dye based on a disulphidebis(ethylsulphone/monochlorotriazine) reactive system has been investigated. Relatively high degrees of exhaustion and fixation were achieved for cotton fabrics dyed with the disulphidebis(ethylsulphone/monochlorotriazine) reactive dye compared to bifunctional sulphatoethylsulphone/monochlorotriazine and/or conventional monofunctional monochlorotriazine reactive dyes. The results also indicate that the fastness properties are approximately the same for all the dyes studied in this investigation.     

Investigation into the dyeing of wool with Lanasol and Remazol reactive dyes in seawater

Freshwater is an increasingly scarce resource that is extensively used in textile wet‐processing. In seeking to identify alternative low freshwater‐usage coloration technology, this study examined the potential use of seawater (SEAW) as the dyeing medium for wool coloration using a range of reactive dyes. Initially, the dyeing behaviour of the wool fabric in simulated seawater (SSW) was compared with conventional dyeing from distilled water (DW) using α‐bromoacrylamide‐based Lanasol dyes and sulphatoethyl sulphone‐based Remazol dyes. These preliminary studies demonstrated that comparable coloration could be achieved in the SSW medium based on an assessment of the dye exhaustion, dye fixation, colour yield and levelness. Subsequent dyeing studies of wool using Mauritian seawater with both the Lanasol and Remazol reactive dyes confirmed that, based on the dye exhaustion, dye fixation, colour yield and levelness, comparable coloration could be achieved, highlighting the possibility of substituting freshwater with seawater as the dyeing medium.     

Reactive dyeing of silk using commercial acid dyes based on a three‐component Mannich‐type reaction

Acid dyes are employed for commercially dyeing silk, which results in ionic bonds between the silk fibroin and the dye. This generally leads to low wet fastness properties for dyed silk fabrics. In this work, three commercial acid dyes with aromatic primary amine structures were selected to dye silk using a Mannich‐type reaction, resulting in improved wet fastness of dyed silk by forming covalent bonds between silk fibroin and dye. The Mannich‐type reactive dyeing was applied to silk fabrics at both 30 and 90°C in trials. Dyeing at 90°C can shorten the dyeing time compared with dyeing at 30°C, even although dye exhaustion and relative fixation at 90°C were a little lower. The dyeing process was optimised when the dyeing temperature was 90°C, dyebath pH 4, dye‐to‐formaldehyde ratio 1:30 and holding dyeing time 60 minutes. The results showed that the dye exhaustion on silk fabrics for the three aromatic primary amine‐containing acid dyes exceeded 94% and their relative fixation was over 80%. Their washing and rubbing fastness reached grade 4 or higher. Hence, the colour fastness properties of dyed silk fabrics using the Mannich‐type reactive dyeing method is superior to the conventional acid dyeing method using the same aromatic primary amine‐containing acid dyes. The Mannich‐type reactive dyeing for silk fabrics at 90°C can be developed into a novel and rapid reactive dyeing method, promising an effective dyeing process with excellent colour fastness.     

Design, synthesis and application of easy wash-off reactive dyes

New dyes that not only give good fixation levels but also relatively low substantivity in the hydrolysed form were the targets of this research. Our approach involved lowering the substantivity of the hydrolysed dye by reducing the planarity that is required for dyes to have high substantivity on cotton. In this regard, bifunctional bis-dichlorotriazine (bis-DCT) and tetrafunctional bis-monochlorotriazine/bis-sulphatoethyl sulphone [bis-(MCT/SES)] reactive dyes were made, using selected diaminobiphenyls. Bis-DCT bifunctional reactive dyes were applied to cotton by a pad–batch method, while bis-(MCT/SES) tetrafunctional reactive dyes were applied to cotton by a pad–dry–cure. Following dye application, it was found that the resultant hydrolysed dyes easily washed off the fibre surface and that the dyed cotton fabrics had colour fastness to rubbing and laundering properties that were comparable with the commercial prototypes used in this study. However, it is also apparent that the combination of relatively low water solubility and large molecular size has an adverse effect on fibre penetration.     

Optimal dyeing systems for resistance to the physical strength loss of the PLA/cotton blended fabric

In this study, optimization of disperse/reactive dyeing systems for resistance to the physical strength loss of Poly(lactic acid) (PLA)/cotton blended fabric was investigated. The blended fabric underwent a two‐bath, two‐stage dyeing process in which the PLA component of the blended fabric was dyed using two disperse dyes, followed by the cotton component being dyed with six reactive dyes containing different reactive groups—dichlorotriazine, monochlorotriazine, sulphatoethylsulphone, monofluorotriazine, monochlorotriazine/sulphatoethylsulphone, and monofluorotriazine/sulphatoethylsulphone groups. The optimal dyeing systems were established according to the fixation rate of the dyes, tear/tensile strength loss, and SEM micrographs of the fabric. To avoid the strength loss during the disperse/reactive dyeing process, the recommended disperse dyeing conditions were 110°C, pH 5 for 20 min, whereas the reactive dyeing conditions should be temperature ≤60°C and alkali concentration ≤3 g/L. In this regard, reactive dyes containing monofluorotriazine and monofluorotriazine/sulphatoethylsulphone groups were especially suitable for the reactive dyeing systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fixation of reactive dyes using radio-frequency energy

Radio-frequency (r.f.) energy has been used to increase the fixation rate of reactive dyes on cotton fabric in pad-batch dyeing. A parallel-plate r.f. applicator was used to heat batches of fabric containing reactive dye formulations. The time required for fixation of the dyes was reduced from several hours to a few minutes by heating the fabric in the radio-frequency field. Reactive dyes incorporating three different types of reactive groups, vinylsulphone, nicotinic acid, and mixed vinylsulphone/ monochlorotriazine were studied and found to be applicable using the hot pad-batch method. The colour yield and wash fastness of dyeings with the vinylsulphone/monochlorotriazine bifunctional dyes using r.f.-assisted fixation was equal or superior to those of dyeings performed by conventional cold pad-batch dyeing methods.     

An analysis of the substantivity of hydrolysed reactive dyes and its implication for rinsing processes

Substantivity plays a key role in dyeing processes, for dye exhaustion and fixation as well as for dye removal during rinsing. The latter is especially relevant for reactive dyes when the hydrolysed dye has to be removed from the fibre. The substantivity of the hydrolysed form of 46 commercially important reactive dyes was analysed at two temperatures for a wide range of dye amounts, pH values and electrolyte concentrations. The results showed that substantivity was highly dye‐specific and varied, for each variable analysed, almost within the entire theoretically possible range of values. Substantivity values correlated best with the number of sulphatoethylsulphone groups in the dye molecule and dye solubility in the presence of sodium chloride. Sensitivity to electrolyte, pH, dye amount and temperature broadly correlated with each other, implying that a reduction in electrolyte concentration and an increase in pH and temperature are more beneficial in the removal of highly substantive reactive dyes. Some dyes remained highly substantive even at 90 °C, indicating that dye removal in industrial processes, too, would be difficult. For dyes with little substantivity, however, wash baths at the boil do not appear to be necessary, neither is the significant removal of electrolyte before rinsing at elevated temperature.     

One-bath dyeing of polyester/cotton with disperse and bis-3-carboxypyridinium-s-triazine reactive dyes. Part 1: Factors limiting production of heavy shades

Over the last 20 years, selected disperse dyes and bis-3-carboxypyridinium- s -triazine reactive dyes have been widely promoted for the exhaust dyeing of polyester/cotton blends in a one-bath-one-stage ('all-in') process under neutral conditions. However, despite the time and energy savings afforded by this elegant dyeing process, there is a belief in the dyeing industry that economical production is limited to pale and medium depths of shade. In this paper, the two dye classes (disperse dyes on polyester and bis-3-carboxypyridinium- s -triazine reactive dyes on cotton) have been investigated to understand why heavy depths of shade cannot readily be obtained economically using this process.     

Ultrasonic‐assisted dyeing: I. Nylon dyeability with reactive dyes

The use of ultrasonic power (38.5 KHz, 350 W) to assist the dyeability of nylon‐6 fibre with reactive dyes is reported. The effects of the different factors that may affect the dyeability of nylon‐6 fibre with Reactive Red 55 were simultaneously carried out under both ultrasonic power and conventional heating conditions. The colour strength values obtained for the dyed samples using ultrasonic power were higher than those obtained using conventional heating. Also, the effect of alkaline soaping treatment on dye fixation for the dyed fabrics with different reactive dyes, at both acidic and neutral pHs, is generally better with ultrasonic than with conventional heating. The overall results indicate that the enhancing effect is mainly attributed to the de‐aggregation of dye molecules, which leads to better dye diffusion and possible assistance for dye‐fibre covalent‐bond fixation. The results of wet fastness properties of the dyed fabrics reveal improvement using ultrasonic power dyeing relative to the conventional heating method. © 2003 Society of Chemical Industry     

Design and application of a multifunctional reactive dye capable of high fixation efficiency on cellulose

A polyfunctional reactive dye containing two dichloro- s -triazine residues linked through aliphatic amino groups via a third triazine system to the chromophoric residue has been prepared. The dye was synthesised stepwise from a specially synthesised 2,4-dichloro- s -triazine dyes. The first step is the reaction of both carbon–chlorine sites in the 'parent' dye with 2 mol ethylenediamine under selected conditions of pH and temperature; these conditions ensure that only one of the amino groups in the ethylenediamine will react to give the bis-2,4-aminoethyleneaminotriazine dye. The second step is the condensation of 2 mol cyanuric chloride with the two pendant primary amino groups. The alkylamino-linked dichloro- s -triazine dyes show very different dyeing properties when compared with those shown by the parent dichloro- s -triazine dye, which has the reactive group linked directly into the aromatic chromophore; in particular, the new dyes have high fixation efficiencies when dyed on cotton at 50 °C and the dye–fibre bond stability to boiling acidic conditions is very good.     

Reactive dyeing of cellulosic fibers: Use of cationic surfactants and their interaction with reactive dyes

Cotton fabrics were dyed with three reactive dyes, C.I Reactive Blue 263, C.I Reactive Red 269, and C.I Reactive Yellow 208, after pretreatment of the fabrics with three alkyl trimethyl‐ammonium bromides (tmabs) having 12, 14, and 16 carbon atoms in the alkyl chain. The pretreated samples were dyed with standard dyeing methods using conventional, reduced amounts of electrolyte, and no electrolyte. Pretreatment with the three cationics (tmabs) resulted in an increase in dye exhaustion with all dyes used, whereas total dye fixation was lower for both red and blue dye and equal for the yellow, when compared to the reference untreated samples dyed according to the same standard dyeing method. The interaction between dodecyl trimethyl‐ammonium bromide and the three dyes was studied and the stoichiometry of the various dye/dodecyl trimethyl‐ammonium bromide (12‐tmab) complexes formed has been deduced. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A new approach to the dyeing of silk with sulphatoethylsulphone dyes

A new approach to the dyeing of silk with sulphatoethylsulphone dyes, based on ß-elimination before dyeing, has been investigated. Some factors affecting both (β-elimination and dyeing have been studied. The improved dyeing process shows a high degree of dyebath exhaustion and excellent fixation in the absence of salt, thus reducing the risk of environmental pollution from salt and dyes.     

锦纶66微纤维活性染料染色条件探讨

采用毛用和棉用活性染料对锦纶66微纤维染色,详细讨论了染色温度、染浴pH值、染色和皂洗方法对染色深度和固色率的影响,分析了不同类型的活性染料对染色条件的敏感性。活性染料对锦纶66微纤维的染色深度、固着率和固着效率受温度、pH值、染料母体结构和活性基的影响很大。毛用活性染料更适合于锦纶66微纤维的染色,普通乙烯砜硫酸酯及乙烯砜硫酸酯/一氯均三嗪染料可有选择性地加以使用,毛用活性染料合适的染色pH值约为4,其它染料适用的pH值因品种而异。采用酸性染色或先酸性后碱性的染色条件均可,后者的优点是固着效率高,但染色深度未见提高染色后采用碱性条件皂洗有利于染色深度的提高。