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.     

Dyeing of wool with temporarily solubilised disperse dyes

Temporarily solubilised disperse dyes derived from aminophenyl-4-(β-sulphatoethylsulphone) have been applied to wool fabric without the use of a levelling agent. By virtue of their characteristic dye structure, excellent levelling properties were observed on wool fabric. Good exhaustion, fixation and fastness test values were also obtained.     

Effect of Sandospace R on the dyeability of gamma-irradiated wool,wool/polyester and polyester fabrics with some disperse dyes containing amino groups

The effect of Sandospace R on the dyeability of gamma-irradiated wool, wool/polyester and polyester fabrics towards disperse dyes has been investigated. The effects of the different factors that may affect the colour yield of the dyed samples (such as radiation dose, Sandospace R concentration, pH strength of the dye bath, dye concentration, dyeing temperature and time were studied. In general, and regardless of the studied factor, the irradiated fabric showed a significant dye affinity for the disperse dyes employed compared/to the unirradiated fabrics. However, the different fabrics irradiated to a dose of 2Mrad showed the highest colour strength with a high level of dyeing. Also, it was observed that a concentration of Sandospace R as low as 0·5% effectively enhances the dye affinity for the disperse dyes used here. Moreover, it was found that the pH of the dyeing bath at which the highest colour strength obtained was 3. Increasing the dye concentration up to 4% based on fabric weight, caused a significant enhancement in the colour strength, whilst raising/the dyeing bath temperature from 60°C to 100°C appreciably accelerated the rate of dye uptake. Complete exhaustion absorption of the disperse dye occurred over a period of 2h. © 1998 Society of Chemical Industry     

Use of a novel water-soluble arylating agent to dye wool and wool blends with disperse dyes

A series of water-soluble fibre-reactive arylating agents were synthesised and evaluated from the stand-point of improving fibre coloration with disperse dyes. In particular, the compound, sodio-2,4-dianilino-6-[4'- β -sulphatoethylsulphonylanilino]- s -triazine (FAA 200) was found to be promising; this compound could be applied in the same bath as a disperse dye at pH 5–6. Under the latter conditions this compound showed high substantivity to wool and at the boil readily underwent β -elimination of the sulphate ester residue to give the vinyl sulphone reactive group which adds on to nucleophilic sites in the fibre to form a covalent bond. Coapplication with commercially available disperse dyes gave bright, level dyeings that exhibited promising wet fastness. FAA 200 was used as an auxiliary to dye disperse dyes on both fibre components of a wool–polyester blend fabric; it was found that addition of hydrogen peroxide or sodium thiocyanate was necessary to obviate reduction of certain disperse dyes when dyeing at 120 °C.     

One-bath dyeing of wool/polyester blends with acid and disperse dyes. Part 2 — disperse dye distribution on polyester and wool

Disperse dye distribution on polyester and wool during one-bath dyeing of wool/polyester blends is discussed. The addition of carriers increases the wool's intrinsic saturation value for disperse dye, thus raising the degree of staining on the wool component at the low dye uptakes. However, staining can be minimised if the dyeing is close to or attains equilibrium conditions. Sequestering agents can accelerate the disperse dye diffusion out of the wool fibre, further reducing staining on wool and transferring more disperse dyes from wool to polyester. Citric acid can be used as a sequestering agent as well as a pH adjusting agent.     

The Modification of Wool with Reactive Hydrophobes

A series of seven reactive hydrophobic compounds was synthesised and authenticated. Aqueous dispersions of these compounds were prepared by milling and applied to wool by pad–dry–steam and exhaustion procedures. The extent of fixation achieved was assessed by determining the weight gain of the treated wools. Treated wool fabric was transfer printed with disperse dye papers and the disperse dye affinity was assessed both by dye yield (K/S) measurements and by determining the     

Benzoyl peroxide-induced graft polymerization of 2-methyl-5-vinylpyridine onto polyester/wool blend

Graft polymerization of 2-methyl-5-vinylpyridine (MVP) onto polyester/wool blended fabric was carried out using benzoyl peroxide as initiator. The graft polymerization reaction was conducted under a variety of conditions. The graft yield increased by increasing benzoyl peroxide concentration from 0.559 mmole/l. to 1.657 mmole/l. Further increase in benzoyl peroxide concentration (i.e., up to 2.795 mmole/l.) decreased grafting. Increasing the MVP concentration from 4% to 10% caused a significant enhancement in grafting. The same held true for raising the polymerization temperature within the range of 65°–85°C. The grafting reaction proceeded initially at a fast rate and decreased with time to a slower rate. The grafted samples showed improved dyeability toward acid dye, increased density, and decreased moisture regain as compared with the untreated blend. Furthermore, a tentative mechanism for initiation of grafting was suggested.     

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.     

One‐bath union dyeing of wool/polytrimethylene terephthalate blends†

The one‐bath dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool has been investigated. The exhaustion of selected Terasil disperse dyes on PTT fibre and Lanasol reactive dyes on wool was measured as a function of temperature, together with the cross‐staining of the Terasil dyes on the wool component and the Lanasol dyes on PTT component. Most Terasil disperse dyes achieved satisfactory dye uptake on PTT at 110 °C, whereas on conventional polyester (polyethylene terephthalate) temperatures of up to 130 °C are required. An optimised union‐dyeing technique for wool/PTT blends was developed which minimised the staining of Terasil disperse dyes on wool and produced dyed goods with high levels of wet colour fastness. Carriers were not required to enhance the dyeability of PTT at low temperatures. The wool component appeared to be protected against damage at 110 °C by the reactive dyes. The results indicate the potential for blending PTT fibre and wool to produce fabrics that are easier to dye at lower temperatures than conventional wool/polyester blends.     

Phospholipid bilayers as vehicles of anthraquinone disperse dyes in wool dyeing

The use of multilamellar lipid vesicles as carriers of disperse dyes on wool fibres has been studied. Liposomes made from egg phosphatidylcholine containing the anthraquinone dye CI Disperse Violet 1 at different phospholipid/dye concentrations were used. The physical stability of these systems was assessed by measuring the mean vesicle size distribution of lipid vesicle suspensions after preparation and during dyeing. Kinetic aspects involving dye adsorption and bonding on untreated and chlorinated wool samples by means of the liposomes at different dye/lipid ratios were also investigated. This process led to the controlled dye exhaustion on wool, directly dependent on the relationship between the dye and lipid components, with a clear improvement in the dye-fibre bonding forces and in the dispersing efficiency, compared with conventional dispersing agents. The optimum dye exhaustion was reached for the dye/phospholipid concentrations 0.53 and 1.0 mmol/l respectively. The maximum amounts of dye bonded on untreated wool fibre were obtained for the same dye/lipid molar ratio. However, chlorinated wool samples showed a slight decrease in the total bonded dye as the chlorination level increased.     

羊毛活性/分散染料染色染料相互作用研究

在一定工艺条件下，用活性染料染羊毛，再用分散染料套染，其K／S值大于单独使用活性和分散染料染色的K／S值之和，活性染料对羊毛起到了改性作用，使分散染料染色湿牢度有显著提高。随着活性染料浓度的增加，分散染料的上染率也增加。用分散染料套染活性染料，其匀染性相对于单独使用活性染料有提高。     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Enhancing the wash fastness of disperse dyes on wool with oxidants

Disperse dyes are not currently applied to wool commercially, in large part because of inadequate wash fastness, but they do have potential, especially for wool‐polyester blends. In this study, for the first time hydrogen peroxide was investigated to increase the wash fastness of disperse dyes on wool. In the absence of oxidants, 10 disperse dyes from seven classes imparted colours with a range of depths (K/S 2‐26) with wash fastness (grey scale ratings for colour change) grades of 3 to 4‐5. Hydrogen peroxide had only small effects on colours and gave only small enhancements to wash fastness, which were limited to anthraquinone, nitrodiphenylamine, disazo and coumarin dyes. The bleach activators Prestogen W and citric acid enhanced the bleaching effect of hydrogen peroxide but did not assist with raising wash fastness. Hydrogen peroxide in post‐dyeing scouring made the dyeings brighter but did not significantly enhance wash fastness. Ammonium persulphate, which was included for benchmarking with earlier studies, yellowed the wool and decomposed some dyes. This study extends the range of dye classes whose wash fastness on wool can be improved by ammonium persulphate to now include diazo, coumarin and methine, and confirms that oxidants/free radical initiators have potential for enabling the disperse dyeing of wool.     

Modification of wool fabric using ecologically acceptable UV‐assisted treatments

Wool fabric was modified using ecologically acceptable treatments in order to enhance its shrinkage and pilling resistance. Wool fabrics were irradiated with ultraviolet light for different period of times. The UV‐irradiated wool fabrics were then treated with an oxidising agent (hydrogen peroxide or sodium monoperoxyphthalate) or a protease enzyme (papain or savinase 16L type EX). Treatment of wool fabric with these systems was found to be effective in reducing its pilling and shrinkage without severe loss in weight and strength of the fabric. Chemical and mechanical analyses of the treated samples compared with the untreated one are reported. Transmission electron microscopy investigation of the untreated and treated wool samples was used to identify the histological component in wool keratin affected by these treatments. Copyright © 2005 Society of Chemical Industry     

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.     

Studies of the chemical modifications of wool and their effects on the wool–water relationship. Part II. Wool-water relationships of modified and unmodified wool

The wool–water relationships of the modified wools prepared as described in Part I of this series have been studied. The drained water content of fabric and the solution isotherms and diffusion constants of water vapor into untreated and modified wools have been measured. Most of the treated wool fabrics showed considerable decreases in the drained water contents compared with the untreated wool. However, the degree of improvement depended markedly on the conditions of modification, particularly with the styrene grafted materials. In some cases values close to those of a comparable polypropylene fabric were found. The sorption isotherms also showed that the modifications reduced, substantially in some cases, the regains even when calculated on the wool content only. The diffusion constants were difficult to measure because of the heats of sorption causing temperature changes during the sorption; however, at lower regains this effect could be corrected. It was found that both the direct chemical modification and the grafted wools showed a diffusion behavior which was more characteristic of hydrophobic materials in that the diffusion constants tended to decrease with increasing concentration. At low humidities the diffusion constants were larger than in the untreated wool, but at higher humidities lower diffusivities were found with the modified wools.     

Dyeing properties of wool treated with liquid ammonia

Wool fibre and fabric have been treated with liquid ammonia and their surface characteristics investigated by means of SEM and ESCA techniques. The treated specimens were dyed with levelling and milling acid dyes. Although no changes in nitrogen content and fibre surface properties were detected, their dyeing rate was increased considerably as was saturation dye exhaustion. Dyeing properties were similar to those of wool treated with low-temperature plasmas by glow discharge. Fabrics treated with liquid ammonia were dyed at various temperatures in the range 30–80°C, and dye uptake was similarly increased.     

Effect of metal ion binding of chitosan on the printability of pretreated wool fabric

In this study, chitosan was used as a pretreatment agent for wool fabric to increase the metal binding during the mordanting process with copper sulphate. The copper(II) binding was measured by measuring volumetrically the concentration of metal ions that remained in the solution after mordanting. The pretreated mordanted wool samples were then subjected to printing with a natural dye, 2-hydroxy-1,4-naphthoquinone (lawsone). The results indicate that color strength and wash fastness of the pretreated printed wool samples were enhanced compared to the untreated samples. This enhancement depends mainly on the molecular weight and concentration of chitosan.     

Effect of atmospheric pressure helium plasma on felting and low temperature dyeing of wool

Wool fabrics were treated with atmospheric pressure helium glow discharge plasma in an attempt to improve felting and dyeing behavior with cold brand reactive dyes using cold pad‐batch method at neutral pH. On glow plasma treatment, the hydrophilicity of wool surface and its resistance toward felting was greatly improved without any significant damage to the cuticle layer. The color strength of the plasma treated dyed wool on the surface (in terms of K/S) was found to be nearly double of the color strength of dyed untreated wool fabric. However, the corresponding total dye uptake of the treated wool increased by a much lower value of 40%–50%. The reason behind this altered dyeing behavior was investigated by studying the dye kinetics using infinite bath and surface characteristics using SEM and SIMS. It was found that the glow plasma treatment greatly transformed the chemical surface of the wool fibers. It resulted in uniform removal of hydrophobic cuticular layer, which resulted in better diffusion of the dye molecules into the fiber, and formation of hydrophilic ? NH₂ groups near the surface, which helped in anchoring the dye molecules close to the surface giving higher color strength than expected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of polydopamine deposition on wool fibers on the construction of melanin

The use of dopamine to synthesize melanin as a natural dye on fabrics has the disadvantages of complicated processing, long processing time, and high cost. This study simplifies the processing conditions of the oxidative polymerization of dopamine and develops wool fabric melanin coatings with different finishing effects by adjusting the reaction time. The results of computer color matching, ultraviolet (UV) protection properties, and color fastness indicated that the treated wool fibers were effectively dyed, and they achieved UV resistance properties comparable to those realized in other studies in a relatively short time. The degree of lightness (L) and UV protection factor of the treated fabric reached up to 13.3 and 80+, respectively. Samples W/PDA 60 and W/PDA 120 absorbed more than 95% of the UV light. The color fastness was greater than Grade 4. The Fourier infrared spectrum and X-ray diffraction studies revealed that the chemical and crystalline structures of the wool fiber did not change significantly after the treatment. The breaking strength of samples W/PDA 60 and W/PDA 120 was about 50% higher than that of the original wool fabric. This efficient and simple method provides a feasible and promising solution for the color deepening and UV finishing of high value-added wool products. It can be a potential choice for upgrading the printing and dyeing industries from the perspective of ecological protection.