Application of the channel flow cell to the investigation of dyeing kinetics and mechanism: new perspectives on dyeing processes

The ability of the channel flow cell to probe reactions at a solution/non-conducting solid interface makes it a powerful method for investigating dyeing reactions. The technique gives direct information about the surface concentrations of dye at the fibre surface and thus allows the elucidation of dyeing mechanisms and the determination of kinetic parameters. The experimental realisation of the channel flow cell in this context and its basic theory are outlined and the strength of the methodology illustrated with investigations of various reactive dyes and model acid dyes. These studies ailow a generalised model of dyeing phenomena to be proposed.     

Telechelic PEG-polymers end-capped with chromophores: Using as cationic reactive dyes and salt-free dyeing properties on cotton fabrics

In this article, telechelic polymers containing polyethylene glycol (PEG) moieties as space groups were combined with chromophores to synthesize cationic reactive dyes (BCD-R, BCD-Y, and BCD-B). The salt-free dyeing performance of these telechelic polymeric cationic reactive dyes on cotton fabrics was evaluated. The exhaustion and fixation of the dyes in salt-free dyeing was above 89.33 and 77.22%, respectively. The color fastness of dry rubbing for the three dyes reached grade 4–5, and their color fastness to light reached grade 5–6. Their washing fastness also reached grade 4–5, except for that of BCD-Y (grade 3–4). The results showed that the dyes possessed good leveling and build-up properties and substantivity to cellulose fiber. The zeta potential (ξ-potential) of dyed fabric was estimated, and it was found that the ξ-potential of the fabrics increased after dying with telechelic polymeric cationic reactive dyes, and the more dye that was used, the greater ξ-potential increase. The exhaustion curves of dyes were also determined, and they were much different from those of anionic reactive dyes. The adsorption kinetics and isotherms of BCD-R were investigated. It was found that the pseudo-second-order kinetic model gave the best fit of the experimental data at all three tested dyeing temperatures (25, 45, and 65°C) with R² values over 0.998. Both the Langmuir and Freundlich models could be used to describe the adsorption of BCD-R onto cellulose fibers and the Langmuir model fit the experimental data better than the Freundlich model. The thermodynamic parameters (ΔG, ΔS, ΔH, and activation energy) of the dye adsorption process were researched further. The results indicated that the adsorption of BCD-R onto cotton fibers was spontaneous and exothermic and that after adsorption onto the cotton fibers, the degree of freedom of the dye decreased.     

Electrochemical oxidation of reactive dyes: method validation and application

Electrochemical oxidation is a very effective technique for wastewater processing and, in the textile industry, it can be employed to remove colour from residual dyeing and washing liquors. In previous studies, the main factors were established for the control of the electrochemical removal of reactive dyes from textile wastewater. Mathematical models were proposed for the decolorisation of these dyes and for the electrical consumption. In the present work, these models are analysed and a three-step methodology is established in order to determine whether a dye can be removed from wastewater by electrochemical treatment. This methodology is applied and verified on a further four reactive dyes. The mathematical models are also employed to evaluate the colour removal from textile wastewater samples containing reactive dyes.     

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 accelerating effect of a small cationic quaternary ammonium compound and the adsorption kinetics in the dyeing of silk with reactive dyes

In order to develop an eco‐friendly method for silk reactive dyeing that uses a lower accelerant dosage to achieve a higher dye fixation, hexyl dimethyl octyl ammonium chloride was synthesised as an accelerant for the dyeing of silk with reactive dyes. The accelerating effect, corresponding adsorption kinetics, and interaction mechanisms among hexyl dimethyl octyl ammonium chloride, reactive dyes, and silk were investigated. At hexyl dimethyl octyl ammonium chloride concentrations of 10.8–14.4 mm , the dye fixations for three reactive dyes were much higher than those achieved with sodium sulfate, even though the required dosages of hexyl dimethyl octyl ammonium chloride were 30–40 times lower than those of sodium sulfate. The wash fastness, rub fastness, light fastness, K/S, and colour difference values after dyeing with hexyl dimethyl octyl ammonium chloride were similar to those obtained using sodium sulfate, and silk can be dyed uniformly. The adsorption kinetics followed a second‐order kinetic model. The activation energies of surface adsorption for the three reactive dyes were lower than those of sodium sulfate. The high fixation of reactive dyestuffs and the low required dosage of hexyl dimethyl octyl ammonium chloride demonstrate that the use of this new accelerant provides a novel, highly efficient method for silk dyeing. A possible acceleration mechanism of hexyl dimethyl octyl ammonium chloride for reactive dyes adsorbed on the surface of silk was proposed, based on a series of activation parameters of the adsorption process.     

Physico-chemical modelling of the dyeing of cotton with reactive dyes

Over the past decades a great deal of research effort has been devoted to understanding the physico-chemical mechanism of the dyeing of cotton with reactive dyes. However, the use of physico-chemical models has been almost exclusively restricted to research laboratories due to the simplifying assumptions used. A more practical model has now been developed and is intended to allow dyeing recipes and the process parameters used in bulk production to be optimised. The model is additionally able to quantify the effect of non-controllable variables on overall dyeing efficiency.     

锦纶66微纤维活性染料染色条件探讨

采用毛用和棉用活性染料对锦纶66微纤维染色,详细讨论了染色温度、染浴pH值、染色和皂洗方法对染色深度和固色率的影响,分析了不同类型的活性染料对染色条件的敏感性。活性染料对锦纶66微纤维的染色深度、固着率和固着效率受温度、pH值、染料母体结构和活性基的影响很大。毛用活性染料更适合于锦纶66微纤维的染色,普通乙烯砜硫酸酯及乙烯砜硫酸酯/一氯均三嗪染料可有选择性地加以使用,毛用活性染料合适的染色pH值约为4,其它染料适用的pH值因品种而异。采用酸性染色或先酸性后碱性的染色条件均可,后者的优点是固着效率高,但染色深度未见提高染色后采用碱性条件皂洗有利于染色深度的提高。     

中国染料工业现状与发展趋势

综述了与纤维成物理结合的染料类别、染色对象、染色原理与染色性能现状;详细论述了与纤维成化学结合的反应性染料染色原理和染色性能及其发展,包括反应基团类型、单反应基团反应性染料、双反应基团反应性染料、发色体结构对双反应基团反应性染料染色性能的影响;简介了大分子交联染料的分子结构及适应现代纤维数码喷墨印花需求的染色性能。     

Studies on Some New Reactive Disperse Dyes

The preparation of some new reactive disperse dyes which can be used for dyeing 100% synthetic and fibre blends is described. The preparation of some disperse dyes containing a chlorohydrin group is also described. This radical is the precursor of the epoxide reactive group in the active form of these dyes. Dyeings produced on various fibre blends by a two–stage high–temperature and by a carrier–dyeing technique are assessed. It was found that dyeings produced by the high–temperature technique were brighter, more level and possessed much better technical properties than those obtained using the carrier–dyeing method. The fastness properties of dyed samples were determined and found to be comparable with those of conventional disperse and reactive dyes. The colour yield was also determined in order to examine the possibility of obtaining deep dyeings on blended fibres, and to evaluate the potential commercial use of these dyes for dyeing blends as well as 100% synthetic–polymer fibres.     

世界染料与染整工艺科技创新

根据染料母体的生物相容性论述了非诱变性染料和仿生染料在纺织纤维着色中的发展方向；论述了实现高固色率活性染料的有效途径以及通过交联染色方法实现染料与纤维近100％化学结合的可行性；介绍了环境友好染色新工艺，活性染料无盐染色，还原染料和硫化染料生化法还原或电还原法染色，非水溶剂染色以及喷墨印染技术。     

Reactive dyes containing a benzimidazolone residue

During the investigation of dyeing properties of reactive dyes containing a benzimidazolone residue the negative influence of salt concentration on their exhaustion was demonstrated. In the case of model dyes not containing the reactive group, change in aggregation state at various temperatures was investigated. It has been shown that the reactive dyes containing a benzimidazolone residue may undergo excessive aggregation in concentrated sodium chloride solution. This may cause difficulties in the dyeing process.     

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.     

季铵型阳离子活性染料

本文综述了季铵型阳离子活性染料的理论与实践纤维素纤维在染浴中解离出羟基负离子,阳离子型活性染料在静电作用下吸附,提高了活性染料的亲和力和直接性,这种作用正是普通活性染料染色过程中无机盐所起的作用,因而阳离子型活性染料在染色中可大量减少甚至不使用无机盐,并可以大幅度提高染料的固色率,降低印染成本,缩短和简化印染流程,大量降低染色废水的排出。阳离子型活性染料大致分为两类:一类是阳离子在活性染料分的母体上,另一类是阳离子在活性基上。染料中阳离子主要有芳胺类季铵盐和脂肪族季铵化合物:染料的的化学结构类型主要是偶氮类、蒽醌类和杂环类,其合成方法与普通活性染料大同小异阳离子型活性染料是普通活性染料性能改进与提高的主要途径之一有25篇参考文献。     

多活性基活性染料及其拼混应用

活性染料已成为最重要的染料类别，多活性基染料是染料的发展方向。本文叙述了常见几类活性基团的特性以及活性基团间桥接基对染料性能的影响。两类多活性基染料已具有商业价值：根据染料的相客性、染色条件以及染料的结构特性来选择拼混染料。不同类染料可以进行拼混。两种相同活性基团的多活性基染料的拼混可以得到很好的拼混染料，国外已经提出并发表了多种类型的拼混情况。拼混应用已成为活性染料重点研究的方向之一。     

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.     

Optimal dyeing systems for resistance to the physical strength loss of the PLA/cotton blended fabric

In this study, optimization of disperse/reactive dyeing systems for resistance to the physical strength loss of Poly(lactic acid) (PLA)/cotton blended fabric was investigated. The blended fabric underwent a two‐bath, two‐stage dyeing process in which the PLA component of the blended fabric was dyed using two disperse dyes, followed by the cotton component being dyed with six reactive dyes containing different reactive groups—dichlorotriazine, monochlorotriazine, sulphatoethylsulphone, monofluorotriazine, monochlorotriazine/sulphatoethylsulphone, and monofluorotriazine/sulphatoethylsulphone groups. The optimal dyeing systems were established according to the fixation rate of the dyes, tear/tensile strength loss, and SEM micrographs of the fabric. To avoid the strength loss during the disperse/reactive dyeing process, the recommended disperse dyeing conditions were 110°C, pH 5 for 20 min, whereas the reactive dyeing conditions should be temperature ≤60°C and alkali concentration ≤3 g/L. In this regard, reactive dyes containing monofluorotriazine and monofluorotriazine/sulphatoethylsulphone groups were especially suitable for the reactive dyeing systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

竹/棉混纺织物活性染料染色使用代用碱固色的工艺探讨

通过代用碱TF-221和常规纯碱对活性染料浸染固色的对比实验,测定了碱剂在染色浴固着反应中pH值的动态变化值。通过染色K/S值、各项色牢度、上染速率的对比实验,讨论了代用碱TF-221在活性染料染色中代替纯碱作为固色剂的作用效果,并测定两种工艺染色后织物的强力变化,找到合适的固色工艺。实践证明:代用碱TF-221完全可以代替纯碱用于活性染料染色对竹/棉混纺织物染色时的固色,其固着浴pH值稳定范围符合活性染料的染色特征,可以获得与使用纯碱相当或高于的K/S值和染色牢度,且上色缓慢,起到匀染作用;染色后织物的强力无明显下降。     

活性染料对莲纤维的染色性能研究

为了了解活性染料对莲纤维的染色性能,采用单因素分析法,在改变温度、浴比、时间、元明粉浓度、纯碱浓度等工艺条件下,分别采用两种不同类型的活性染料对莲纤维进行染色,并测试其上染率、固色率、耐皂洗色牢度和耐汗渍色牢度。结果表明:活性大红X-3B上染莲纤维的最佳染色工艺为染色温度40℃,染液浴比1∶40,染色时间60 min,元明粉质量浓度20 g/L,纯碱质量浓度30 g/L;活性嫩黄X-7G上染莲纤维的最佳染色工艺为染色温度40℃,染液浴比1∶50,染色时间60 min,元明粉质量浓度10 g/L,纯碱质量浓度20 g/L;活性染料耐皂洗色牢度和耐汗渍色牢度都在3级以上。     

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.     

棉盖丙复合针织物活性/碱性染料同浴染色工艺探讨

在用次氯酸钠溶液进行氯漂/氯化的基础上,重点研究了用活性染料/碱性染料同浴对棉盖丙复合针织物染色时,分散剂的用量、碱剂的用量、染色温度、染色时间等因素对染色效果的影响。试验结果表明:当 IW分散剂用量为2．5g/l时可获得比较好的分散效果,弱碱性条件下棉的色差很小,丙纶的色差也可以接受; 温度低时,对碱性染料上染丙纶不利,90℃时染色效果较好,同浴染色时间增加,色差明显增大。