A hemicyanine fluorescent reactive cationic dye: synthesis and applications on wool fabrics

A novel hemicyanine fluorescent reactive cationic dye was synthesised by the reaction between the free amino group of a hemicyanine fluorescent dye and 2,3‐dibromopropionyl chloride. The dye was characterised by proton nuclear magnetic resonance spectroscopy, high‐resolution mass spectrometry, ultraviolet‐visible absorption spectrometry, and single‐photon fluorescence spectrometry. The prepared dye was applied to wool fabrics to give fluorescent orange shades. The colour fastness of the dyed wool fabrics was tested. Results show that dyed fabrics using the novel hemicyanine fluorescent reactive cationic dye could be used as fluorescent clothing.     

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.     

One‐bath union dyeing of a modified wool/acrylic blend with acid and reactive dyes

Pretreated wool/acrylic fibre was obtained by a facile amidoximation process. Fibre characterisation (nitrogen content, tensile strength, shrinkage, infrared spectra and X‐ray diffraction) proved the success of the pretreatment. Union dyeing of wool/acrylic fabrics with acid and reactive dyes, namely CI Acid Red 40, CI Acid Blue 25, CI Reactive Red 194 and CI Reactive Blue 25, was obtained using a one‐bath dyeing process. Different factors that may affect the dyeability of the blend fibre, such as dyebath pH, liquor ratio, temperature, time and dye concentration, were evaluated with respect to the dye exhaustion, fixation, colour strength, levelling and fastness properties. Excellent to good fastness was obtained for all samples, irrespective of the dye used. The result of the investigation offers a new viable method for union dyeing of wool/acrylic fibres in a one‐dyebath process.     

Synthesis and application to cellulose of reactive dye precursor of anti‐bacterial N‐halamine

To achieve textile dyeing and functional finishing in one process, a bleach‐resistant reactive dye precursor to anti‐bacterial N‐halamine was synthesised by reacting a type of dichlorotriazine reactive dye with 4‐amino‐2,2,6,6‐tetramethylpiperidine. The synthesised compound, which can be transformed to an N‐halamine molecule by exposure to dilute bleach solution, was used to dye cotton fabrics. After exposure to a dilute sodium hypochlorite solution, dyed cotton fabrics showed excellent anti‐bacterial properties against Staphylococcus aureus and Escherichia coli O157:H7, facilitating a ca. 6‐log reduction in bacteria within a short period of contact. Compared with the dichlorotriazine reactive dye, the reactive dye precursor demonstrated comparable dyeing properties including exhaustion and fixation values. No differences in rub fastness, wash fastness or bleach fastness were detected between fabrics dyed with, respectively, dichlorotriazine reactive dye and the reactive dye precursor to N‐halamine.     

Dyeing of N-modified viscose rayon fibres with reactive dyes

Modified viscose rayon fibres were produced by incorporation of different doses of a polydiallyldimethylammonium chloride based additive in the viscose dope prior to spinning. On dyeing the modified fibres with different reactive dyes, excellent dye exhaustion and total dye fixation above 90% were obtained without the use of electrolyte and with low salt concentration. Exhaustion and total dye fixation showed an exponential relationship. The wash fastness properties of the dyed fibres were excellent and the light fastness showed a slight drop in the modified fibres. The presence of the amino groups along with low density and crystallinity of the modified fibres may be responsible for the enhanced dyeability.     

Improving the dyeability of wool by treatment with chitosan

A study of pretreatment of wool fabrics with chitosan by a pad-dry method has been carried out. The pretreatment effectively eliminates differences in dyeing behaviour between damaged and undamaged wool fibres, with an increase in the rate of dye uptake and the exhaustion of acid and reactive dyes. Penetration of the fibre by dyes has been followed using fluorescence microscopy and the role of the chitosan coating in the dyeing process clarified. Similar colour fastness properties were obtained on both untreated and chitosan-treated wool fabrics. The chitosan coating on wool fabrics has been examined by scanning electron microscopy. Evidence for the presence of chitosan was sought using a colorimetric method. It is believed that an approximately uniform and adherent chitosan sheath is formed on individual wool fibres.     

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.     

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.     

Synthesis and dyeing properties of polyvinylamine dyes for cotton

Novel polyvinylamine dyes were designed and synthesised from poly(N‐vinylformamide‐co‐vinylamine) and reactive dyes, then used to dye cotton fibres by the dip‐pad‐steam process, with the dyeing methods being examined in detail. Each polyvinylamine dye was fixed to cotton without a crosslinking agent through covalent bonds formed between the reactive group of the dye and the cotton fibres. A fixation of 99% was achieved, with grades of 4 and 4‐5 wash and dry‐rub fastness, respectively.     

Studies toward a universal dye for textile fibres

A new organic dye was synthesised as part of an approach to producing a dye that could be applied to any of a variety of widely used fibre types. The dye synthesised is best described as a disperse-reactive dye and was obtained from a sequence of reactions that used an acid yellow dye as a starting compound. Dichlorotriazine was used as the reactive group in the target dye and the chemical structures of the new dye and its precursors were confirmed using ¹H NMR, mass spectrometry and FTIR analyses. In the neutral form, the dye was suitable for polyester, nylon and wool fibres. When the pH was adjusted to 9 it dyed cotton, albeit in a pastel shade only. By adding N, N -dimethylethylenediamine to the dyebath, the dye could be applied to acrylic fabric at pH 5. The fastness of the dyed fibres was also evaluated.     

Synthesis and application of a novel,triphendioxazine‐based,phosphorus‐containing acid dye for wool

A novel phosphorus‐containing acid dye based on triphendioxazine was designed and synthesised from diphenylamine through a series of reactions. The dye has a navy‐blue colour, high molar extinction coefficient of 5.32 × 10⁴ l/mol·cm, and high substantivity for dyeing wool in a salt‐free, aqueous dyebath. A high exhaustion value of 98.2% on wool fabrics was recorded at 3% omf and a liquor ratio of 1:20. The wash fastness values of the acid dye, including colour change and staining on cotton and wool, were grades 5, 4 and 4–5, respectively. The dry and wet fastness are grades 4–5 and 4, respectively. In addition, light fastness reaches grades 6–7 at 3% omf dye concentration. These dye properties are better than those of commercial triphendioxazine dyes, for example, CI Direct Blue 106 and CI Reactive Blue 198, under analogous dyeing conditions.     

The Anomalous Fading of Some Fluorescent Dyes and Brighteners on Hydrophilic Fibres

The fastness to light of a number of fluorescent yellow dyes and fluorescent brightening agents (FBA) on several fibres at different concentrations has been assessed both visually and by colour-difference measurements. One acid dye on wool, six FBA on wool and two FBA on cotton showed anomalous fading (i.e. the light fastness decreased with increasing concentration). Results of extraction experiments showed that this could be accounted for by the formation of coloured decomposition products from the dye or FBA and, with wool, from the fibre also. With FBA on wool and cotton there appears to be an optimum concentration above which both the fastness to light and the whiteness fall.     

One-bath dyeing of wool/acrylic blends with reactive cationic dyes based on monofluorotriazine

A series of reactive cationic dyes containing the monofluorotriazine structure has been synthesised and their dyeing behaviour on wool, acrylic and a 50:50 wool/acrylic blend studied using a one-bath method. The results indicate that reactive cationic dyes having this structure give a high level of exhaustion and fixation on these fibres. Fastness properties on the wool/acrylic blend were also in general very good.     

Synthesis of methine dyes derived from indol‐2‐ones and their dyeability on polyester fibres

Three series of methine dyes were synthesised by the condensation of indol‐2‐ones with aryl acroleins. The structures of these dyes were confirmed by ¹H nuclear magnetic resonance spectroscopy, infrared spectrometry and elemental analysis. The ultraviolet‐visible absorption spectra of the dyes were examined in different solvents. The maximum absorption wavelength ranged from 386 to 495 nm. The dyes were applied to polyester fibres, and the colour gamut and dyeing properties were investigated. Results showed that the dye uptake (percentage exhaustion) was 86.9–92.0%, with the hue changing from yellow to red. The rubbing fastness, wash fastness, and sublimation fastness were between 4 and 5.     

Improvement of the dyeing and fastness properties of a naphthalimide fluorescent dye using poly(amidoamine) dendrimer

In this study, 4‐amino‐9‐methoxypropylnaphthalimide fluorescent dye (dye 1 ) was reacted with poly(amidoamine) dendrimer G = ?0.5 to prepare a naphthalimide–dendrimer hybrid dye (dye 2 ). The chemical structures of the synthesised dyes were confirmed by elemental analysis, Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and ultraviolet‐visible spectroscopy. The solvatochromism of the dyes was evaluated in various solvents with respect to visible absorption properties, and positive solvatochromism was observed by solvent polarity change from chloroform to ethanol. The dyeing ability of the synthesised dyes was investigated by their application onto nylon fabric, and nylon substrates dyed with dye 2 exhibited marked enhancement both in terms of colour strength and general fastness properties. The results of this study clearly demonstrated the high potential and performance of dye 2 as a novel promising fluorescent dye as compared with dye 1 . Overall, it was inferred that the modification of the naphthalimide fluorescent dye with poly(amidoamine) denderimer could markedly improve the dyeing and fastness properties of the naphthalimide fluorescent dye on nylon fabrics.     

Dyeing of nylon with reactive dyes. Part 2. The effect of changes in level of dye sulphonation on the dyeing of nylon with reactive dyes

Four mono-functional reactive monochlorotriazinyl (MCT) dyes, each derived from the same chromophore and possessing a single monochlorotriazinyl reactive group, but differing only in degree of sulphonation, were synthesised and evaluated on nylon. The colour yield, degree of exhaustion, fixation, and the fastness properties of each dye were assessed. Initial exhaustion, at pH 4, was high for all dyes but percentage fixation, via covalent bond formation, increased with increasing levels of sulphonation. In all cases fixation efficiency reduced markedly with increasing concentrations of dye applied.     

Dyeing of cotton with a bifunctional disulphide bis(ethylsulphone-sulphatoethylsulphone) disazo reactive dye

A new bifunctional disazo reactive dye of a temporarily high molecular structure based on a disulphide bis(ethylsulphone-sulphatoethylsulphone) reactive system was synthesised and applied to cotton fabric. This dye displayed good primary exhaustion under different neutral exhaustion conditions. The results assessed for the alkaline exhaust dyeing indicate that the disulphide bis(ethylsulphone-sulphatoethylsulphone) dye showed higher exhaustion and fixation values compared to those obtained with the commercial CI Reactive Black 5. The fastness properties of the disulphide dye were similar to those of the commercial dye. Received: 24 March 2005; Accepted: 15 June 2005.     

Application of sodium benzoyl thiosulphate from aqueous solution to wool and its effect on substantivity of disperse dyes. Part 1: synthesis and characterisation of sodium benzoyl thiosulphate

The introduction of bulky aryl residues into wool fibres not only enhances their disperse dyeability but also improves their settability, shrink resistance and imparts easy‐care properties. It would be highly desirable for colourists to achieve such effects when dyeing or printing wool from an aqueous solution as wool/polyester blend fabrics could be dyed and printed with the same dye; furthermore, in the case of an all‐wool fabric pretreated with such arylating systems, following dyeing or printing with disperse dyes, dye fixation can be achieved by dry heat procedures. A water‐soluble, fibre‐reactive arylating agent, sodium benzoyl thiosulphate, was therefore synthesised, characterised and its stability to hydrolysis in aqueous media was examined.     

活性染料用于拉细羊毛染色的研究

研究了四类活性染料染拉细羊毛的工艺条件和十二个染色配方。与媒介染料相比，用活性染料对拉细羊毛染色可获得更好的效果。染料的溶解度、匀染性、上色率、固色率均好于媒介染料，颜色的批差小。研究结果表明：除煮呢沾色牢度外，染色羊毛的各项牢度均优于媒介染料。     

Dyeing of poly(lactic acid) fibres with synthesised novel heterocyclic disazo disperse dyes

Poly(lactic acid) (PLA) is the first melt‐processable, renewable, sustainable and biodegradable natural‐based synthetic fibre. It has a broad range of uses and combines ecological advantages with outstanding performance in textiles. PLA fibre, as an aliphatic polyester, can be dyed with disperse dyes. Apart from the limited number of commercial disperse dyes, disperse dye exhaustion on PLA is generally lower than that on  poly(ethylene terephthalate) (PET). In this study, new heterocyclic disazo disperse dyes, substituted with methyl, nitro and chloro groups at their ortho‐, meta‐ and para‐ positions, synthesised in our previous study, were applied to PLA and PET fibres to examine their dyeing performance, and colour fastness and dye exhaustion properties. Different shades of yellow, orange, reddish brown and brown were obtained. Most of the synthesised novel heterocyclic disazo disperse dyes exhibited good build‐up properties with high K/S levels on both fibres. Para‐ bonding substituent provided higher K/S values than meta‐ and ortho‐ positions for –NO₂ and –Cl substituents for both fibres. Overall, the most synthesised novel heterocyclic disazo disperse dyes in this study exhibited good build‐up properties with high K/S, exhaustion and wet fastness levels on both PLA and PET fibres.