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.     

Pad-Batch Dyeing of Wool Fabric—Development of an Industrial Process*

This paper describes an industrial procedure developed for the application of dyes of good fastness properties, especially reactive dyes, to wool fabric by a pad-batch technique, following the initial observations (7) that by dyeing from concentrated solutions of urea the rates of diffusion and of reaction of reactive dyes with wool are greatly increased. The chemical and mechanical developments necessary to apply this initial observation under practical dyeing conditions are described.     

Reactive dyeing systems for wool fibres based on hetero-bifunctional reactive dyes. Part 2: Investigation of dyeing properties during the dyeing cycle

The dyeing behaviour during the dyeing cycle of a Sumifix Supra dye and some other commercial reactive dyes under various dyebath pH conditions was investigated. Studies of the dyeing of wool serge fabric indicated that the diffusion properties of hetero-bifunctional Sumifix Supra dyes generally lie between those of b-sulphatoethylsulphone (Remazol dyes) and monochlorotriazine (Procion H dyes).     

Protection against phototendering of wool by metal salts and mordanted dyes

Samples of treated and dyed wool have been irradiated with an artificial UV radiation source with a spectral distribution that matched the summer solar UV spectrum. The extent of phototendering was determined by measuring the loss of tensile strength of strips of wool fabric. Many of the dyes studied accelerated phototendering, although some metal-complex dyes prolonged the lifetime. Significant protection of wool against phototendering could be obtained by treatment with aluminium salts, or related salts, followed by dyeing with classical mordant dyes.     

Reactive dyeing systems for wool fibres based on hetero-bifunctional reactive dyes. Part 1: Application of commercial reactive dyes

The wool dyeing properties, such as exhaustion and fixation parameters, of selected hetero-bifunctional Sumifix Supra dyes and some other commercial reactive dyes were quantified under various dyebath pH conditions. Studies of the dyeing of wool serge fabric indicated that Sumifix Supra dyes could produce reasonably high fixation values. However, remarkably improved fixation values were obtained when these dyes were pre-activated to the vinylsulphone form and dyed in this form, especially at low pH values (pH 4 or lower).     

Research in the cold pad–batch dyeing process for wool pretreated by hydrogen peroxide

The cold pad–batch dyeing process of wool pretreated by hydrogen peroxide was carried out with Lanasol reactive dyes and Realan reactive dyes. The influences of various conditions of the dyeing process, including urea dosage, sodium bisulphite dosage, pH value, batching time and the liquor pickup on colour yield, were analysed. Fixation, levelness of dyeing, dye penetration, colour fastness, breaking strength and elongation were compared between untreated and treated wool fabrics. The study showed that cold pad–batch dyeing of wool fabric is a good prospect for future use because of the resulting advantages, such as higher fixation yield, less energy usage and lower sewage discharge.     

牡丹花天然植物染料对羊毛织物染色性能的研究

将黄色牡丹花天然植物染料用于羊毛织物的染色,探讨了媒染剂和染色方法对羊毛织物染色效果的影响,通过单因素试验和正交试验筛选出以明矾为媒染剂时牡丹花黄色染料对羊毛织物的最佳染色工艺条件,得到了色泽鲜艳的黄色羊毛织物.     

Synthesis of acid dyes containing polyetheramine moieties and their low‐temperature dyeing properties on wool fiber

To realize the low‐temperature dyeing of wool fibers, the use of auxiliaries and wool modification are common methods. Low‐temperature auxiliaries may cause water‐pollution problems, and wool modification is a costly and uncontrollable process. In this study, new acid dyes, named D1–D3, containing polyetheramine groups were synthesized and applied to wool fiber by conventional and low‐temperature exhaust dyeing procedures. The results indicate that the new acid dyes could interact with wool‐fiber‐like auxiliaries and render a high exhaustion rate to the wool fiber at a dyeing temperature of 80 °C. In comparison with Acid Blue 25, the D1–D3 dyes showed an increased dyeing rate, especially under a dyeing temperature of 80 °C. Despite the bigger relative molecular masses of D1–D3, the exhaustion rates of D1–D3 were still higher, and the times of half‐dyeing were shorter than that of Acid Blue 25. The color differences between the wool fabrics dyed with the four dyes at 80 and 98 °C, respectively, were compared. We found that the color differences of D1–D3 between 80 and 98 °C were smaller than that of Acid Blue 25. The interactions between the dyes and wool fiber were analyzed and manifested by the measurement of the ζ potential of the dyes and wool fiber. The leveling and transfer properties of the D1–D3 dyes were also investigated, and the color differences of the wool fabrics dyed with Acid Blue 25, D1, and D2 were very low at all measured pH values and temperatures. The fastnesses of D1–D3 on wool fabric were almost the same as that of Acid Blue 25. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45793.     

Dyeing natural fibres in supercritical carbon dioxide using a nonionic surfactant reverse micellar system

A reverse micellar system in supercritical carbon dioxide has been developed as a dyeing medium. Water-soluble dyes such as reactive dyes and acid dyes could be sufficiently solubilised in the interior of a specially constituted reverse micelle. Protein fabrics, silk and wool, were satisfactorily dyed even in deep shades with conventional acid dyes without any special pretreatment. Cotton cellulose fabric was also dyed with conventional reactive dyes when the electrostatic force of repulsion between dye and cotton was eliminated. Compared to previously proposed supercritical dyeing methods, dyeing of fabrics with this system could be performed at low temperatures and pressures in a short time.     

The Covalent Reactions of Primary Amino Side-chains and Disulphide Bonds in Wool Keratin

Previous work on the reactions of different types of reactive dyes with wool is reassessed and new jindings presented. The decrease in reactivity of basic wool side chains to reaction with 1:fluoro:2:4 dinitrobenzene after wool has been dyed with acidic or reactive dyes is further investigated. New and previous correction factors measuring the extent of this inactivation are compared. Using such corrections, the extent of actual covalent binding of reactive dyes to basic wool side chains is determined. Applying these corrections gives reasonable stoichiometry in the dye-fibre reaction. The extent of reaction of thiols, basic and hydroxyl groups in wool with five reactive dyes of different classes has been measured, and compared for two dyeing methods (long-liquor and urea pad-batch). The differences and similarities in the extent and type of reaction of the dyes with the fibre sites, using the two methods of application, is discussed. The role of disulphide degradation in reactive dyeing is further investigated. The effect of alkaline treatments on the fixation of reactive dyes, and the availability of wool lysine side-chains for reaction (in the urea pad-batch dyeing system) is reported upon.     

The use of ultraviolet radiation in an adsorbable organohalogen-free print preparation for wool and in wool dyeing: the Siroflash process

German legislation controlling the discharge of adsorbable organohalogens (AOX) in process effluents has focused attention on the need for environmentally acceptable alternatives to chlorination as a prepare-for-print (PFP) treatment for wool. The Siroflash process is a novel AOX-free approach which involves continuous UV irradiation of dry wool fabric, followed by conventional wet oxidation using hydrogen peroxide or permonosulphuric acid. Although permonosulphuric acid or peroxide treatments alone are ineffective as a PFP, the colour yields of prints on Siroflash-treated fabric are similar to those on chlorinated wool. The synergistic interaction between UV exposure and wet oxidation results in high levels of cystine oxidation, cuticle damage and loss of soluble protein, all of which are highly specific to irradiated surface fibres. UV irradiation of wool can significantly increase dyeing colour yields. The use of 1:1 metal-complex dyes is particularly effective, and a 3% o. w. f. dyeing on UV-treated fabric can produce a better depth of shade than a 5% dyeing on untreated fabric.     

The Effect of the Shape of the Exhaustion Curve on Levelness of Dyeing

Exponential exhaustion curves were found experimentally to give more level uptake of dyes on wool than linear exhaustions or recommended temperature-time procedures taking the same time. This conflicts with predictions from ‘significant dyeing rate’ theory.     

A novel technique to minimise energy and pollution in the dyeing of linen fabric

Garments made from linen fabrics have a natural feel and drape. Most commercially available direct and reactive dyes have only a moderate affinity for this cellulosic fibre, although this lack of affinity can be overcome by the use of electrolytes. As a result, high volumes of wastewater containing large amounts of chemicals are discharged from the typical cellulosic material dyehouse. The ‘no‐salt dyeing’ of linen fabric with reactive and direct dyes was achieved by treating linen fabrics with chitosan in a microwave oven. After using the novel dye method, no observed enhancement of either wash or light fastness properties was seen. Dyebath reuse for both reactive and direct dyes was carried out in order to reduce the environmental impact of the dyes. This dyeing method was then applied to dyeing linen fabrics, with each of the items of clothing subjected to layout and cutting according to the design’s patterns; the dyeing results are discussed in this paper.     

The effect of reactive dyes on damage in wool dyeing

This paper demonstrates that reactive dyes exert a significant fibre–protective effect when dyeing wool fabric; this effect may be measured, in a reproducible manner, using the wet–burst strength test. The effect of dyebath pH, dye concentration, dyebath temperature and dyeing time on wool can thus be evaluated. The magnitude of the above protective effect has been compared with that achieved using commercially available fibre–protective agents. It is concluded that reactive dyes are significantly more effective than the latter agents when employed in medium to full depths. It is proposed that the unusual protective effect afforded by reactive dyes is related to the following factors. Reactive dyes readily react with sulphur nucleophiles, thus inhibiting thiol–disulphide interchange reactions and thereby significantly interfering with the level of set produced in a boiling dyebath. Reactive dyes react preferentially with non–keratinous proteins in the intercellular cement and the endocuticle thus reducing their tendency to hydrolyse and to partially dissolve in the hot aqueous dyebath.     

Investigation and feed-forward neural network-based estimation of dyeing properties of air plasma treated wool fabric dyed with natural dye obtained from Hibiscus sabdariffa

In the colouring processes of textile products, more environmentally friendly chemicals and finishing methods should be used instead of conventional ones that harm the environment every day, so that alternative realistic ways to protect nature, both academically and industrially, could be possible. Due to some inconveniences caused by synthetic dyes that are widely used today, in this study, ultrasonic dyeing of wool fabric with Hibiscus sabdariffa was carried out after environmental-friendly air vacuum plasma application which increased the absorption of the dyes into the textile material. According to the performance results, colour strengths of the wool fabrics were increased significantly. Surface morphology analysis was carried out and etching effects of air vacuum plasma treatment were clearly seen on the micrographs of the treated wool fabrics. An environmental-friendly green process was achieved through this study and it was concluded that vacuum air plasma treatment could be an alternative green-process as a pretreatment to increase the dye up-take of natural dyeing treatment. Moreover, in this study, a feed-forward neural network (FFNN) model was presented and used for predicting the dyeing properties (L, a, b and K/S) of samples. The experimental results showed that the presented model achieves the regression values greater than 0.9 for all dyeing properties. Consequently, it was considered that the proposed FFNN was successfully modelled and could be efficiently utilised for dyeing characteristics of wool fabrics dyed with natural dye extracted from Hibiscus sabdariffa.     

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.     

Differential dyeing of wool fabric with metal‐complex dyes after ultraviolet irradiation

Experiments were conducted to investigate the ultraviolet irradiation of wool fabric as a pretreatment for differential dyeing. Wool fabric was irradiated using a medium‐pressure mercury lamp in order to obtain, on the irradiated area, increased dye uptake under the same dyeing conditions as untreated wool. The chemical modification of the fibre surface as a result of ultraviolet irradiation was confirmed by an increase in metal ion absorption and hydrophilicity, in agreement with Fourier Transform‐infrared–attenuated total reflectance spectra, although scanning electron microscopy showed that the fibre morphology was unaffected. A selection of 1:1 metal‐complex dyes was used to show the maximum colour difference between irradiated and untreated areas of the fabric. The experiments focused on two effects: a double face with the same shade but different depths (greater depth on the treated side), and a double face with different shades. The latter effect was achieved by dyeing the irradiated fabrics with mixtures of acid and metal‐complex dyes. Rubbing and washing fastness evaluations at 50 °C confirmed that the dyeings after irradiation with the selected 1:1 metal‐complex dyes scored identically to conventional dyeings.     

New Approaches to Washfast Dyes for Wool:

The possibility of using isothiuronium salts as ‘protected’ reactive dyes for wool has been examined. In principle, it should be possible to apply chromophores containing such salt groups as cationic dyes and to ensure levelness while they are still in the unreactive salt form. By raising the pH of the dyebath they could then be hydrolysed to insoluble thiol dyes, which could bind covalently to cystine residues in the wool by a thiol / disulphide interchange reaction. Various model isothiuronium salts have been synthesized and a study made on the effect of S- and N-substituents on the ease of hydrolysis to thiol. The β-isothioureidopropion-anilide structure is proposed as a suitable group upon which a series of dyes could be based. Commercial Alcian (ICl) dyes, which contain isothiouronium salt groups, are shown to be unsuitable as ‘protected’ reactive dyes for wool because of their instability in hot solution. Mechanistic reasons are advanced to account for their sensitivity to hydrolysis.     

羊毛混纺织物的染色

羊毛混纺织物兼容多组分纤维的性能,优点明显,但是染色工艺复杂,成本较贵.因此,研究开发新型染料及新型染色方法对羊毛混纺织物的染色具有重要意义.本文综述了羊毛/腈纶、羊毛/锦纶、羊毛/蚕丝、羊毛/Tencel等羊毛混纺织物的染色现状及进展.     

Mordant dye application on cotton: optimisation and combination with natural dyes

It is well known that cotton fibres can be dyed through the formation of coordinate bonds involving cellulose chains, mordants such as alum, and natural dyes such as alizarin. Similarly, synthetic dyes known as mordant acid dyes can be used to dye wool fibres. Unlike mordant dyes on wool, the fastnesses of natural dyes on cotton are often low. Although concerns surrounding textile sustainability have sparked renewed interest in the use of natural dyes, extensive replacement of synthetic dyes with natural dyes is neither practical nor fundamentally possible. However, similarities in dyeing methods using mordant and natural dyes raise the possibility of using mordant dyes as alternatives to natural dyes in the dyeing of cotton. Further, the potential for combining suitable dyes from these two classes to expand the colour gamut currently available from natural dyes on cotton seem worthy of exploration. The results of this study indicate that shades comparable with those produced by natural dyes can be obtained on cotton using select mordant dyes following Fe²⁺ and Al³⁺ pretreatments. The best results were obtained using a two‐step/two‐bath process and dyes such as CI Mordant Blue 13 and CI Mordant Orange 6. In evaluations of mordant and natural dye combinations using the two mordant dyes logwood and Osage orange as prototypes, interesting fabric shades were obtained. However, the fastness properties of these dyes must be improved in order to produce commercially viable dyeings.