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1 – 10 of 143Quratulain Mohtashim, Muriel Rigout and Sheraz Hussain Siddique Hussain Yousfani
Sulphur dyes provide an inexpensive medium to dye cellulosic fibres with heavy shade depths. They offer moderate to good fastness to light and wet treatments. However, owing to…
Abstract
Purpose
Sulphur dyes provide an inexpensive medium to dye cellulosic fibres with heavy shade depths. They offer moderate to good fastness to light and wet treatments. However, owing to the environmental hazard produced by the use of sodium sulphide, the practical implication of these dyes is steadily decreasing. Moreover, these dyes are prone to oxidation causing pronounced fading on exposure to laundering. This paper aims to present the green processing of sulphur dyes by using a biodegradable reducing agent in place of sodium sulphide to dye cotton fabrics. The study also proposes after-treatments with tannin to improve the fastness properties of the dyeings.
Design/methodology/approach
In this study, dyeings were produced on cotton fabric with a range of C.I. Leuco Sulphur dyes, which were reduced with sodium sulphide and glucose. Sulphur dyeings were after-treated with an environment-friendly tannin-based product (Bayprotect CL (BP)); subsequently, the after-treated samples were evaluated for colour strength, wash, light and rubbing fastness.
Findings
A novel after-treatment method was developed, which substantially improved the wash fastness of C.I. Leuco Sulphur Black 1 dyeing to ISO 105 C06/C09 washing. However, the degree of this improvement varied for the other sulphur dyes used. The surface morphology and the possible mechanisms for the improved fastness properties were also discussed.
Research limitations/implications
The effect of after-treatment was significant for improving the wash fastness of sulphur black dyeings in particular, while the effect on other colours was minor. Significant improvements were observed for light and wet rub fastness for most of the dyeings, which signifies the importance of tannins as a finishing agent.
Practical implications
It is observed that the tannin-based product, BP, is found to provide the photoprotective effect by improving the lightfastness of the dyeings. Future research may involve the exploration of various tannins as a finishing agent to sulphur dyeings.
Originality/value
This novel finishing technique is found significant for improving the wash fastness of sulphur black 1 dyeings for both the reducing systems. Improvements were also observed for light and wet rub fastnesses for most of the dyeings.
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Based on clarifying the structural difference between jade fibre and general polyester fibre, this paper aims to study the dyeing properties and dyeing adsorption mechanism of…
Abstract
Purpose
Based on clarifying the structural difference between jade fibre and general polyester fibre, this paper aims to study the dyeing properties and dyeing adsorption mechanism of jade fibre with disperse dye and cationic dye.
Design/methodology/approach
The chemical structure and microstructure of jade fibre were briefly explained comparing with ordinary polyester fibre. The dyeing rate curve and dyeing adsorption isotherm of disperse dyes and cationic dyes on jade fibre were, respectively, studied. The dyeing uptake, dyeing absorption mechanism, and the main dyeing process parameters were proposed.
Findings
Jade fibre can be dyed with cationic dye and disperse dye. The suitable exhaust dyeing process is 110°C and 40 minutes for disperse dye, 100°C and 60 minutes for cationic dye. The dyeing uptake on jade fibre with both disperse dyes or cationic dyes is much higher than that on general polyester fibre and acrylic fibre, and the dyeing adsorption mechanism belongs to the combination of Langmuir and Nernst adsorption for disperse dyes and Langmuir adsorption for cationic dyes. Comparing with ordinary polyester fibre, jade fibre has the advantage of low temperature dyeing and reduced effluent, as is significant to energy-saving and emission reduction.
Originality/value
Jade fibre is a new type of modified polyester fibre with the function of health protection and energy conservation. There are little technical data in the literature at present about the dyeing property of jade fibre.
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N.F. Ali, S. Shakra, Y.A. Youssef and T.S. Aysha
New disazo and polyazo ureido reactive dyes incorporating different reactive systems were synthesized and applied to cotton fabric by the exhaust dyeing method. Different factors…
Abstract
New disazo and polyazo ureido reactive dyes incorporating different reactive systems were synthesized and applied to cotton fabric by the exhaust dyeing method. Different factors affecting the dye ability and fastness properties of such dyes are investigated.
Bis(monochlorotriazine) reactive dyes displayed higher primary exhaustion values compared to those obtained with bis(sulphatoethysulphone) and bis(monochlorotriazine/sulphatoethysulphone) reactive dyes under different neutral exhaustion conditions. The results obtained indicate that the fixation efficiencies of these dyes were higher than those of dyes incorporating the bis(dichlorotriazine) reactive system. The results assessed for alkaline exhaust dyeing indicate that the bis(monochlorotriazine/sulphatoethylsulphone) dye was less sensitive to the variation in fixation temperatures than the other reactive dyes. The fastness properties of the ureido reactive dyes were fair to good.
The improved dyeing performance of such type of ureido reactive dyes should lead to the design of reactive dyes with good application and fastness properties on cotton fabric, and provide practical solutions for low-salt dyeing. The present study of synthesis of disazo and polyazo ureido reactive dyes of high molecular structure, and its application to cotton fabric by the exhaust dyeing method is novel and could be applied in the industry.
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Fatma Ali Mohamed and Rafaat Melad Mohareb
The purpose of this paper is to synthesise, characterise and find out properties of some new bifunctional dyes bis (monochlorotriazine) using tetrahydrobenzo[b]thiophene systems…
Abstract
Purpose
The purpose of this paper is to synthesise, characterise and find out properties of some new bifunctional dyes bis (monochlorotriazine) using tetrahydrobenzo[b]thiophene systems as the chromophoric moiety, bearing good colour strength, lightfastness, and other favourable properties.
Design/methodology/approach
The novel reactive dyes were prepared, containing bis monochlorotriazine as reactive groups. The dye is synthesised by diazotization and coupling reactions. Firstly the authors synthesised the ethyl 2‐amino 4,5,6,7‐tetrahydrobenzo[b]thiophen‐3‐carboxylate chromophoric moiety compound which in turn underwent diazotization and coupling then diazotized and coupled reaction with either 1‐amino‐8‐naphthol‐3,6‐disulphonic acid (H‐acid) and or 2‐amino‐8‐naphthol‐6‐sulphonic (γ acid) to give the monoazo dye intermediates compounds. The latter products reacted with 2,4,6‐trichloro‐1,3,5‐triazine in 1:1 molar ratio afforded, via nucleophilic displacement when subjected to condensation 2,4,6‐trichloro‐1,3,5‐triazine in 1:1 molar ratio afforded via nucleophilic displacement, which reacted with 1,4‐phenylenediamine in 2:1 molar ratio to give reaction with the 1,4‐phenylenediamine in 2:1 molar ratio, the bisazobifunctional bismonochlorotriazine reactive dyes.bisazo bifunctional bismonochlorotriazine reactive dyes thus yielding the new target reactive. The synthesised dyes were applied onto cotton fabric under the typical exhaust dyeing conditions and their dyeing properties were investigated.
Findings
The results assessed for dyeing indicate high quality dyeing properties However, the homobifunctional (bis MCT) dyes showed higher exhaustion and fixation values, colour yield and fastness properties.
Practical implications
The described method showed the synthesis of bis monochlorotriazines derived from the tetrahydrobenzo[b]thiophene derivative 3 followed by their application towards cotton fabric.
Social implications
Social implications are to prepare new reactive dyes having higher fastness and uses for dyeing cotton which is the commonest fabric use.
Originality/value
In this work, the novel reactive dyes derived from the tetrahydrobenzo[b]thiophene derivative 3 were synthesized and their structures were based on the analytical and spectral data. Such a group of compounds are considered to be excellent reactive dyes with different colour shades.
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Pitting inhibition efficiency of SO4− and NO3− on AISI 316L stainless steel in contact with Cl−-containing fiber dyeing solutions together with the influence of the anions on…
Abstract
Purpose
Pitting inhibition efficiency of SO4− and NO3− on AISI 316L stainless steel in contact with Cl−-containing fiber dyeing solutions together with the influence of the anions on absorption behavior of the solutions were investigated. The purpose of the study is to experimentally determine an optimized dyeing solution efficient on both – inhibition of the steel’s pitting and exhaustion of the dyes dissolved.
Design/methodology/approach
Methods such as electrochemical cyclic polarization, UV-visible range spectrophotometry and scanning electron microscopy have been used to assess the performance of two inhibitors on both pitting inhibition of the steel and dissolving ability over the reactive dyes. To find out a promising dyeing solution mixture in both aspects, Cl content of the original dyeing solution was replaced gradually with the inhibiting anions, where the total anionic content was kept constant to unchange the dye exhaustion potential of the solution. Then, those solutions came out with diverse pitting inhibition, and dye absorption levels were compared together for reducing/avoiding the pitting issues of the reactive dyeing vessels of the industry.
Findings
Rather high absorption levels detected by visible range spectrophotometry on the solutions showing sound inhibition levels indicated possibility of unaltered reactive dyeing qualities with an enhanced vessel lifetime as the inhibitive anions replace Cl−. Nitrate performed better than sulfate both on inhibition and absorption in the dyeing solutions. Also, 316L vessels became open to an extra anodic protection in inhibitor added solutions.
Research limitations/implications
The findings are valid for a certain group of reactive dyes and dyeing solutions held at 70°C. However, the testing methods are available to almost any dyeing solution and dyeing temperature.
Originality/value
The work presents a combined testing of pitting inhibition and absorption behavior of dyeing solutions involving Cl− that has not been reported so far. It shows that solution recipes least harmful to the steel vessels can be outlined for various reactive or other types of dye groups.
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C.L. Chong, K.W. Yeung and Z.Y. Cui
The dyeing of polyester microfibres with both high energy and low energy disperse dyes has been investigated. The results show the rate of exhaustion on these fibres are more…
Abstract
The dyeing of polyester microfibres with both high energy and low energy disperse dyes has been investigated. The results show the rate of exhaustion on these fibres are more rapid than on regular polyester fibres with no corresponding increase in the colour yield. With the low energy dye, a wide fluctuation in the amount of dye exhausted during dyeing was observed. It is postulated that changes in the degree of crystallinity of microfibres could attribute to such phenomenon.
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Monthon Nakpathom, Buppha Somboon, Nootsara Narumol and Rattanaphol Mongkholrattanasit
The purpose of this study is to investigate the possibility of dyeing polyester (PET) fabric with natural dye extracted from annatto seeds using high temperature dyeing method.
Abstract
Purpose
The purpose of this study is to investigate the possibility of dyeing polyester (PET) fabric with natural dye extracted from annatto seeds using high temperature dyeing method.
Design/methodology/approach
PET fabric was dyed with annatto extract by varying dyeing parameters (temperature, time, pH and dye concentration) to determine the optimum dyeing conditions. The influences of KAl(SO4)2, FeSO4, gallnut mordants or a commercial UV absorber on colour yield and fastness properties were further studied.
Findings
Optimum results were obtained when the fabric was dyed at 130°C for 30 min in a dyebath containing 15 per cent (owf) annatto dye at pH 6. The dyed fabric had an orange shade and exhibited good to excellent wash, crock, perspiration fastness and fair light fastness. Further dyeing with mordants or UV absorber mostly resulted in lower colour yield and similar fastness properties.
Research limitations/implications
Although the light fastness was slightly improved to moderate level for the sample with UV absorber, a noticeable colour staining on cotton portion of multi-fibre fabric occurred when subjected to standard washing test. Compared to C.I. Disperse Orange 73, the annatto dye exhibited comparable colour fastness but had inferior light fastness when dyed at approximately the same colour strength.
Originality/value
Natural colourants from annatto seeds can be used to dye PET fabric at high temperature without mordants, yielding deep orange shade and satisfactory fastness properties. This study provides a promising application to reduce the environmental impact of synthetic dyes.
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H.Z. Shams, Y.A. Youssef, F.A. Mohamed, M.M. El‐Zawahry, M.H. Helal and E.A. El‐Kharadly
The purpose of this paper is to evaluate the efficiency of modifying reactive azo dyes using pyrazolo[1,2‐a]pyrazole fused systems as the chromophoric moiety which could satisfy…
Abstract
Purpose
The purpose of this paper is to evaluate the efficiency of modifying reactive azo dyes using pyrazolo[1,2‐a]pyrazole fused systems as the chromophoric moiety which could satisfy many and varied criteria drawn from economic, synthetic, physicochemical and fastness properties.
Design/methodology/approach
Six novel heterocyclic disazo reactive dyes were prepared, containing monofunctional sulphatoethylsulphone (SES) and hetero‐bifunctional monochlorotriazine (MCT)/SES reactive groups. Dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole chromophoric moieties are initially synthesised and coupled with two different diazonium salts having the aforementioned reactive groups, thus yielding the new target reactive dyes. The synthesised dyes are applied to cotton, wool and silk fabrics under the typical exhaust dyeing conditions and their dyeing properties were investigated.
Findings
The results assessed for dyeing indicate high‐quality dyeing properties. However, the heterobifunctional MCT/SES dyes showed higher exhaustion and fixation values, colour yields and fastness properties than those of the monofunctional SES dyes.
Research limitations/implications
The method developed provided a simple and practical procedure for producing fused pyrazolo[1,2‐a]pyrazole disazo chromophoric systems that afford valuable reactive dyes. In addition, the dyes intermediates based on 4‐arylazo‐1,5‐dioxopyrazolo[1,2‐a]pyrazole as well as their disazo counterparts could be applied as acid dyes to wool and silk.
Originality/value
The method for producing novel disazo reactive dyes could find numerous applications for affording a variety of reactive dyes with different binding linkages and structural reactivity. These could be valuable as reactive dyes with different colour shades.
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This paper describes the colouration of wool with indigo. The wool fabric is pre-treated with different shrink-resist formulations followed by application of indigo. The novel…
Abstract
This paper describes the colouration of wool with indigo. The wool fabric is pre-treated with different shrink-resist formulations followed by application of indigo. The novel dyeing procedure has resulted in commercially acceptable indigo-dyed wool, in terms of improved levelness and reduced yellowness.
While indigo is traditionally applied by the padding technique, in the present work, an exhaust dyeing procedure is investigated. The degree of levellness and the depth of shade are further optimised by varying the pH, temperature and dye concentration. The pH of the dye liquor and the dyeing temperature are found to be critical in achieving level dyeing as well as mitigating fibre damage.
It is found that certain shrink-resist formulations, either applied alone or in combination, give better results in terms of colour yield and fabric handle, while other combinations give poorer results. The dyed samples are found to exhibit excellent wash fastness.
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Fatma A. Mohamed, Saadia A. Abd El-Megied, Mahmoud S. Bashandy and Hassan M. Ibrahim
This study aims to synthesise and characterise new reactive dyes based on thiazole derivatives which act as chromophoric moieties. These dyes were applied to cotton fabric…
Abstract
Purpose
This study aims to synthesise and characterise new reactive dyes based on thiazole derivatives which act as chromophoric moieties. These dyes were applied to cotton fabric, resulting in the dyed fabrics exhibiting good colour strength, light fastness and other fastness properties. The antibacterial activity of the dyed cotton fabric was evaluated against gram-negative and gram-positive bacteria.
Design/methodology/approach
The dyes were synthesised in two steps. First, the coupling compound was formed by adding H-acid solution to cyanuric chloride in an ice bath at pH 5 then adding 4-aminobenzenesulphonic acid portion-wise at room temperature and at pH 6-7. Second, different diazonium salts 4-phenylthiazol-2-amine (2a) and 4-(4-methoxyphenyl) thiazol-2-amine (2b) were coupled with the coupling compound at pH 5. The resultant monochlorotriazine (MCT)-reactive dyes (6a, 6b) were formed. The synthesised dyes were applied onto cotton fabric under typical exhaust dyeing conditions and their dyeing properties were investigated.
Findings
High antimicrobial activity, dye exhaustion and fixation yield on cotton fabric were recorded for each dye. All dyes showed high stability against washing, rubbing, perspiration and light fastness.
Research limitations/implications
Dyeing of cotton fabric with these dyes which have higher fastness, higher exhaustion and higher antibacterial activity is considered one of the most important reactive dyes species.
Practical implications
The preparation procedure showed the synthesis of the novel MCT-reactive dyes derived from thiazole derivatives followed by the application of these dyes on cotton fabrics.
Social implications
Use of reactive dyes will bring a number of benefits to society including higher fastness and higher antibacterial activity so, and these dyes can be used for dyeing cotton.
Originality/value
In this work, the new reactive dyes derived from thiazole derivatives were synthesised and their structures were confirmed by the analytical and spectral data. Such compounds are considered to be excellent reactive dyes with different colour shades and higher antibacterial activity.
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