Synthesis,stability and printing properties of a novel 2‐sulphophenoxy‐4‐chloro‐s‐triazine reactive dye for ink‐jet printing of wool

We report here the synthesis and characterisation of a new medium‐reactivity reactive dye containing 2‐sulphophenoxy‐4‐chloro‐s‐triazine, having enhanced the activity of the chlorine atom for further substitution by the functional groups carried by wool fibre. In addition, a dichloro‐s‐triazine dye was also synthesised for the purpose of comparison. The progress of synthesis reactions and purity of the dyes were determined using capillary electrophoresis and thin layer chromatography. The molecular structure and the chemical compositions of the synthesised dyes were confirmed using Fourier Transform–infrared spectral data and elemental analyses. The inks containing the synthesised dyes were formulated and ink‐jet‐printed onto wool fabrics and then the printed fabrics were steamed at 102°C. Compared with the dichloro‐s‐triazine dye, superior performance in terms of ink stability, K/S and dye fixation was observed for the new 2‐sulphophenoxy‐4‐chloro‐s‐triazine dye. In addition, the light fastness of the fabric printed with the inks containing the new dye was 0.5‐grade greater than that of the fabric printed with the inks containing the dichloro‐s‐triazine dye, and no changes in shade and staining were observed following wash fastness tests of the fabrics printed with the inks containing the new dye.     

Synthesis of a di‐(p‐sulphophenoxy)‐s‐triazine reactive dye and its application in wool fabric ink‐jet printing

Reactive dyes based on p‐sulphophenoxy‐s‐triazines were synthesised, characterised and applied to wool fabric by ink‐jet printing. The extent of dye‐fibre covalent bonding (% fixation) was measured on prints produced using different development methods. The most promising method to obtain high dye‐fibre fixation values was to interleave the printed wool with a pre‐wetted cotton fabric and store for 3 h. Steam fixation was also investigated but gave lower fixation values. The degree of dye hydrolysis vs time in the ink formulation was evaluated because ink stability is critical in commercial operation; a reformulated ink based on a phosphate buffer was found to improve ink stability.     

Kinetic study of the manganese‐based catalytic hydrogen peroxide oxidation of a persistent azo‐dye

BACKGROUND: The discharge of synthetic dyes by the textile industry into the environment poses concerns due to their persistence and toxicity. New efficient treatment processes are required to effectively degrade these dyes. The aim of this work was to study the degradation of a persistent dye (Drimarene Brilliant Reactive Red K‐4BL, C.I.147) using H₂O₂ oxidation catalysed by an Mn(III)‐saltren catalyst and to develop a kinetic model for this system. RESULTS: Dye oxidation with H₂O₂ was significantly improved by the addition of the catalyst. As the pH was increased from 3 to 10, the oxidation rates increased significantly. The kinetic model developed in this study was found to adequately explain the experimental results. In particular, dye oxidation can be described at high pH by pseudo‐first‐order kinetics. A Michaelis–Menton type equation was developed from the model and was found to adequately describe the effect of H₂O₂ and catalyst concentrations on the apparent pseudo‐first‐order rate constant. Optimum catalyst and H₂O₂ concentrations of 500 mg L^?1 and 6.3 g L^?1, respectively, were found to give maximum reaction rates. CONCLUSION: Catalytic H₂O₂ oxidation was found to be effective for the removal of persistent dye and the results obtained in this work are of significance for design and scale‐up of a treatment process. Copyright © 2009 Society of Chemical Industry     

Synthesis and application of KM‐type reactive dyes containing 2‐ethoxy‐4‐chloro‐s‐triazine

A new kind of hetero‐bifunctional reactive dye containing 2‐ethoxy‐4‐chloro‐s‐triazine, with better activity matching with β‐hydroxyethyl sulphone sulphate at a low fixation temperature, was successfully synthesised and characterised. An ethoxy group was designed to be introduced into triazine to increase the substantivity and the reactivity of the dyes. Thereby, the fixation of mono‐s‐chlorotriazine/hydroxyethyl sulphone sulphate (KM‐type) bifunctional reactive dyes on cotton was improved, and dyeing under mild conditions with high fixation was realised. Nineteen dyes with orange, red and blue colours were synthesised and characterised by UV‐Vis and infrared spectroscopy and mass spectrometry. Synthesised dyes were dyed at 60, 75 and 90°C, respectively. Exhaustion and reactivity for all of the ethoxy‐containing KM‐type dyes was over 90% at the optimal temperature, and fixation was over 87%, which was higher than the ethoxy‐free comparative dyes. The optimal fixation temperature of ethoxy‐containing dyes was initially reduced to 75°C, and then to 60°C. Compared with comparative dyes, the wash fastness and light fastness were basically unchanged, and the wet rub fastness of the H‐acid series was reduced by one grade.     

Green synthesis of reactive dye for ink‐jet printing

Chloropyrimidine‐based reactive dyes are reported as well suited to textile printing; however, nucleophilic aromatic substitution of chloropyrimidines with amino‐containing chromophores is slow and often suffers from poor yields. In this study, a novel and simple method was developed for the synthesis of chloropyrimidine‐based reactive dye under microwave irradiation. In addition, the dye was also synthesised by conventional heating for comparison, which took both the reaction time and yield into account. The progress of the synthesis reactions concerned were monitored using capillary electrophoresis and the purity of the dye obtained was assessed by thin‐layer chromatography. The structure of the synthesised trichloropyrimidine dye was confirmed by Fourier Transform–infrared spectroscopy and elemental analysis. It was found that the reaction rate of the nucleophilic aromatic substitution carried out under microwave irradiation was 4‐fold faster than that carried out under conventional heating, although the enhancement in product yield was modest. These results suggest that microwave irradiation is an effective technique for the synthesis of chloropyrimidine‐based reactive dyes. The synthesised chloropyrimidine dye was formulated into an ink and applied onto a wool fabric by ink‐jet printing. The printed fabrics were steamed at 102°C for 5‐25 minutes at 5‐minute intervals. Good K/S and rate of dye fixation were obtained, both of which improved with increasing steaming time. The prints obtained exhibited reasonably good light and wash fastness properties.     

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.     

Technological evaluation of reactive cyclodextrin in cotton printing with reactive and natural dyes

The chemical modification of cotton fabric with reactive cyclodextrin (R‐CD) at different concentrations was carried out to enhance the printability of cotton fabric. The extent of the modification reaction was expressed as %N. Reactive and natural dyes were used to print cotton fabric before and after modification. Printing pastes were applied immediately after preparation or after 24 h of storage. Printing fixation was performed through either steaming or thermal treatment. The effect of the incorporation of R‐CD in the printing paste of unmodified cotton was also studied. The results reveal that the extent of the modification reaction increased with increasing R‐CD concentration and so did the color strength (K/S) of the printed sample regardless of the dye used. The results also revealed that K/S of the R‐CD modified cottons were higher than that of the corresponding unmodified samples regardless of the method of fixation or the time elapsed before printing. On the other hand, the incorporation of R‐CD in the printing pastes of reactive dyes, namely, Cibacron Brown 6R‐P or Remazol Brilliant Red GG, had adverse effects, most probability due to the (a) increasing viscosity of the paste and/or (b) interaction of the reactive dye with R‐CD hydroxyls. The opposite held true when a natural dye was used. Further, the incorporation of R‐CD in the printing pastes had no effect on the rheological type of the pastes or the on overall fastness properties of the prints. Nevertheless, such an incorporation of R‐CD was accompanied by a remarkable increase in the magnitude of the apparent viscosity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 338–347, 2006     

Improving the UV resistance of aromatic poly(l,3,4‐oxadiazole) fiber using a disperse dye modified with octavinyl POSS. Part 1: Preparation of dye and dyeing

Modified dyes were obtained by grafting of disperse dyes with octavinyl polyhedral oligomeric silsesquioxanes (POSS) using a Friedel‐Crafts alkylation reaction and using different ratios of POSS and the original disperse dye. The modified dyes are used to dye aromatic poly(l,3,4‐oxadiazole) (p‐POD) fiber to improve its UV resistance. Then the structure of the modified dye is characterized by Fourier transform infrared spectroscopy and NMR, and the effects of the structure of the modified dye and the dyeing conditions on the UV resistance and color strength (K/S value) of the dyed samples are investigated. The results indicated that the UV adsorption peaks of the modified dye solutions are located at the specified UV wavelengths. The UV resistance of the p‐POD fiber dyed with the modified dye (1:3) can be effectively improved, and the dyed p‐POD fiber can obtain a higher K/S value simultaneously. During the dyeing process, increasing the dyeing temperature and prolonging the dyeing time are both beneficial in improving the anti‐UV ability of the dyed p‐POD fiber; these changes can effectively promote the fixation of dye molecules into p‐POD fibers due to stimulating the motion of dye molecules and p‐POD macromolecules. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44745.     

Sulphite‐based resist styles for digital printing cotton fabrics

Discharge printing provides a method of producing either a white or coloured image on a solid ground fabric; unfortunately, the shade range from this process is limited. An alternative approach to discharge printing is resist printing, which provides prints that are almost indistinguishable from those achieved by the discharge printing process and has the advantage of offering a wider shade range. In resist printing, the resist agent prevents fixation of the background colour by chemical (resist agent inhibits dye fixation) or physical (resist agent inhibits dye absorption) processes and so yields a white print. Printing is carried out on grounds that have been pad‐dry ‘dyed’ with selected reactive dyes; the dyes must not fix during this process otherwise white grounds are not achievable – subsequently fixation is achieved by steaming after digitally printing the resist agent. In this paper, the resist agent studied is sodium sulphite, which selectively blocks reactive groups in reactive dyes – the ground shade reactive dye must be deactivated in this reaction to produce the resist effect. A coloured print may be achieved by incorporating a suitable reactive dye, of a different class to that used in the ground shade, which is not deactivated by the resist agent, in the resist ink.     

Synthesis of novel azo‐containing polyureas derived from 4‐[4′‐(2‐hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione

4‐[4′‐(2‐Hydroxy‐1‐naphthylazo)phenyl]‐1,2,4‐triazolidine‐3,5‐dione ( HNAPTD ) ( 1 ) has been reacted with excess amount of n‐propylisocyanate in DMF (N,N‐dimethylformamide) solution at room temperature. The reaction proceeded with high yield, and involved reaction of both N? H of the urazole group. The resulting bis‐urea derivative 2 was characterized by IR, ¹H‐NMR, elemental analysis, UV‐Vis spectra, and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with Hexamethylene diisocyanate ( HMDI ) and isophorone diisocyanate ( IPDI ) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic azo‐containing polyurea dyes, which are soluble in polar solvents. The polymerization reaction with tolylene‐2,4‐diisocyanate ( TDI ) gave novel aromatic polyurea dye, which is insoluble in most organic solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.22 g dL^?1 in DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3177–3183, 2001     

Synthesis of temporarily solubilised azo disperse dyes containing a β‐sulphatoethylsulphonyl group and dispersant‐free dyeing of polyethylene terephthalate fabric

Disperse dyes containing a β‐sulphatoethylsulphonyl group have temporary solubility and can be applied for dispersant‐free dyeing of hydrophobic fibre. Six novel temporarily solubilised azo disperse dyes having a β‐sulphatoethylsulphonyl group in their structures were synthesised, and their dyeing properties on polyester were investigated. As a dye intermediate, a diazo component having dibromo groups was prepared, and 4‐diethylamino‐4′‐(2‐sulphatoethylsulphonyl‐4,6‐dibromo)azobenzene dyes were prepared by a diazo‐coupling reaction. Then, the dyes containing dicyano groups were prepared by cyanation of corresponding dyes with dibromo groups. The absorption maxima of the dyes were affected by the substituents in the diazo and coupling component rings and varied from 434 to 616 nm in dimethylformamide. Polyethylene terephthalate woven fabric could be dyed with the synthesised temporarily solubilised dyes without using any dispersants. Dyebath pH affected the K/S value at maximum absorption as well as percentage exhaustion on polyethylene terephthalate fabric, and the optimum pH was 5. The dyes gave brownish orange, red, purple, and greenish blue hues on polyethylene terephthalate fabrics, and colour build‐up was good. Wash fastness was good to excellent, rubbing fastness was moderate to excellent, and light fastness was poor to moderate.     

TiO2‐Modified Flower‐Like Bi2WO6 Nanostructures with Enhanced UV‐Vis Photocatalytic Activity

Anatase TiO₂‐modified flower‐like Bi₂WO₆ nanostructures were prepared by a simple hydrothermal reaction followed by layer‐by‐layer deposition and calcination. The photocatalytic activity was evaluated using Brilliant Red X3B, an anionic azo dye, as the target organic pollutant under UV‐Vis light irradiation. The experiment results showed that the photocatalytic activity of the hybrid increases first and then decreases with increasing loading amount of TiO₂. The hybrid coated with four layers of TiO₂ (containing 20 wt‐% TiO₂) showed the highest photocatalytic activity, which is 10.45 and 3.20 times higher than that of pure Bi₂WO₆ and TiO₂, respectively. The improved photocatalytic performance of TiO₂‐modified Bi₂WO₆ nanostructures could be ascribed to the improved light‐harvesting ability, efficient photo‐generated electron‐hole separation, and enhanced adsorption of the dye. This work may shed light on the design of complex architectures and the exploitation of their potential applications.     

The Physical and Chemical Properties of Reactive Dyes and their Effect on Printing Behaviour

The currently available methods of fixation of prints on textiles are reviewed and the influence of the reactivity, diffusion coefficient and substantivity of reactive dyes on their behaviour in printing is described. It is shown how the suitability to the various fixation methods and the stability in alkaline printing paste of reactive dyes can be correlated with the values of reactivity, diffusion coefficient, and substantivity measured by simple techniques. Changes that can be made to the reactivity of a dye by modification of its structure or its application conditions are also illustrated. The influence of hydrolysis of reactive dyes and of breakage of the dye–fibre bond during processing on the fixation achieved is discussed and a method is developed enabling the actual rate of reaction of reactive dyes with cellulose to be calculated.     

Urea/alkali-free printing of cotton with reactive dyes

Urea reduction or elimination in reactive dye print pastes is of ecological interest. Sodium edetate is presented as a complete substitution of urea in the conventional print paste of reactive dyes, namely CI Remazol Black B and Remazol Brilliant Orange 3R using a constant amount of sodium alginate as the thickening agent. Three different print pastes containing urea/NaHCO₃, sodium edetate/NaHCO₃ and sodium edetate were thoroughly investigated. Different factors that may affect the printability of cotton, such as the concentrations of sodium edetate, urea, dye, absence or presence of alkali and steaming time in the prints obtained were evaluated with respect to the dye fixation, colour strength, dye penetration, levelling and the fastness properties. Excellent to good fastness was obtained for all samples irrespective of the print paste used.     

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.     

Ink‐jet printing of cotton with natural dyes

Four natural dyes, annatto, cutch, pomegranate fruit rind, and golden dock, were used as colorants for the preparation of water‐based ink‐jet inks for digital textile printing. The physical and rheological properties (pH, conductivity, surface tension, and viscosity) of the inks were measured over a period of 90 days for the evaluation of ink stability and suitability for ink‐jet printing. The inks were found to be suitable and were used for the digital printing of cotton fabrics. The prints were subjected to wash, light, and rub fastness tests and colour measurements. Colour consistency and fastness results, especially after fixation, are comparable with those of synthetic dyes, which paves the way for the production of environmentally friendly ink‐jet inks using natural dyes for the digital printing of cotton through the formulation of suitable printing techniques.     

Synthesis of some new 2‐[(2,3‐dihydroinden‐1‐ylidene) hydrazinyl]‐4‐methylthiazole derivatives for simultaneous dyeing and finishing for UV protective cotton fabrics

Several 2‐[1‐(1,2‐dihydroinden‐3‐ylidene) hydrazono]‐5‐aryldiazo‐4‐methyl‐1,3‐thiazoles were synthesized by reaction of 1‐(1,2‐Dihydroinden‐3‐ylidene) thiosemicarbazide with different hydrazonyl chlorides. The products are water insoluble and UV absorbers, expressed UPF‐rating values, and their H₂O/DMF solutions were used in simultaneous dyeing and resin finishing of cotton fabrics. Results obtained show that finishing of cotton samples in presence of any of that dyes, irrespective of dye concentration, brings about an improvement in percent nitrogen, wrinkle recovery angle (WRA), dyeability, and UV protection rating values along with slight decrease of tensile strength (TS) compared with the untreated samples. Irrespective of dye structure, increasing the dye concentration from 0.5 and up to 1.7% results in an improvement in the percent nitrogen, TS and a remarkable improvement in both the dyeability, UPF‐rating values along with slight decrease in WRA and lower fastness properties of the treated fabrics. The treated fabrics was characterized using energy dispersive X‐ray analysis indicating the entrapped dye within the fabric structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterisation of microencapsulated 7‐alkyloxy‐4‐trifluoromethylcoumarin dyes

Five new 7‐alkyloxy‐4‐trifluoromethylcoumarin fluorescent dyes were synthesised using the Pechmann and Williamson etherification reactions. The structures of these coumarin dyes were characterised by Fourier Transform–infrared, proton and carbon nuclear magnetic resonance and mass spectra. One of the new coumarin compounds, 7‐isopropyloxy‐4‐trifluoromethylcoumarin, was microencapsulated with melamine–formaldehyde as the shell material by in situ polymerisation. The microcapsules were characterised in terms of Fourier Transform–infrared spectrum, particle size distribution and scanning electron microscopy morphology. The cotton fabric finished with the microencapsulated coumarin dye showed strong fluorescence under ultraviolet light.     

Single‐phase ink‐jet printing onto cotton fabric

The current commercial application of ink‐jet reactive inks to cotton fabrics requires pretreating with pad liquor containing a thickener, urea and alkali prior to printing. In this study, attempts have been made to develop a reactive ink‐jet print in a single‐phase process by adding an organic salt to the ink formulation and hence removing the need to pretreat fabrics. This approach utilises inks containing both a reactive dye, in this case Procion Red H‐E3B, and an organic salt such as sodium formate, sodium acetate, sodium propionate or tri‐sodium citrate. The behaviour of a novel reactive ink formulation for ink‐jet printing on to cotton fabric was evaluated at different pH vlaues. The results at optimum pH indicated that printed non‐pretreated fabrics with ink containing organic salts exhibited a higher level of reactive dye fixation than printed pretreated fabric containing no organic salt ink. The yielded prints demonstrate excellent colour fastness to washing and dry/wet crocking properties. The light fastness of the printed fabrics was improved by adding an organic salt to the ink formulation.     

One‐bath dyeing of polyester/cotton blends with disperse and bis‐3‐carboxypyridinium‐s‐triazine reactive dyes. Part 2: Application of substantive reactive dyes to cotton at 130 °C and neutral pH†

An earlier paper reported that the reactive dyes (not the disperse dyes) were responsible for the inability to achieve heavy depths of shade, when dyeing polyester/cotton blends by a one‐bath process at 130 °C and neutral pH using reactive dyes containing a 3‐carboxypyridinium‐s‐triazinyl group. It was shown that the poor colour yield of the bis‐3‐carboxypyridinium‐s‐triazine reactive dyes was because of their low exhaustion level at 130 °C and pH of 7.0–7.5. We now report the synthesis and evaluation of some bis‐3‐carboxypyridinium‐s‐triazine reactive dye structures, possessing highly substantive chromophores, as a means of obtaining high colour yield, on 100% unmercerised cotton, under the specified dyeing conditions. The technical performance of these dyes under such conditions was compared with that of selected Novacron (Cibacron) LS and Procion H‐E dyes, applied under their recommended (atmospheric) dyeing conditions.