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.     

Haloacetyl reactive dyes-synthesis and application to silk

A series of haloacetyl reactive dyes have been synthesised. The reactivity of haloacetyl groups and the dyeing properties of the dyes on silk fabric were studied. The results show that the bromoacetyl group is more reactive than the chloroacetyl group and molecules containing a bromoacetyl group would dye silk under relatively mild dyeing conditions. Both the exhaustion and fixation on silk fabric are increased if a second reactive group is present in the molecule     

Structure—reactivity studies of a new polyfunctional disulphide bis(ES-MCT/SES) reactive dye applied to silk

A new polyfunctional reactive dye containing disulphidebis(ethylsulphone-monochlorotriazine/sulphatoethylsulphone) reactive system has been synthesised and applied to silk. High exhaustion/fixation results have been achieved at 90 °C and pH 9. The vinylsulphone precursor of the disulphidebis(ethylsulphone) group combined with a sulphatoethylsulphone/monochlorotriazine reactive system confers a relatively high fixation efficiency for this type of polyfunctional reactive dye when compared with that of a conventional bifunctional reactive dye containing the sulphatoethylsulphone/monochlorotriazine reactive system. The results also indicate that high fastness properties were obtained for the reactive dyes under investigation.     

Dyeing of nylon 6 and silk fabrics with a model disulphide bis(ethylsulphone) reactive disperse dye

The synthesis of a new reactive disperse dye containing the disulphide bis(ethylsulphone) group is described. The dye has been applied to nylon 6 and silk fabrics at a variety of pH and temperature conditions. Optimum dye exhaustion and fixation were achieved at pH 8 and 130 °C. The results of dyeings on both substrates indicate that the model disulphide bis(ethylsulphone) reactive disperse dye shows a higher degree of exhaustion and fixation on silk than on nylon 6. The fastness and levelling properties on both fabrics were good.     

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.     

Influence of Eri silk fibre on the physical characteristics and dyeing properties of Eri silk/cotton blended yarn

Different blending ratios of Eri silk and cotton fibres were prepared. The optimum bleaching condition chosen for the blends containing 0–25% silk content was the oxidative bleaching method, whereas the blends at 50–100% should be bleached using the two‐stage bleaching method (oxidative bleaching followed by reductive bleaching). These conditions did affect the force–displacement characteristics of the fibres with no yield point. X‐Ray diffraction results showed that the percentage of crystallinity of the cotton yarn tended to increase after bleaching, whereas the percentage of crystallinity of the Eri yarn decreased marginally. Dyeing properties of the blended yarns were investigated using warm‐dyeing reactive dyes. Percentage exhaustion and the colour yield of the blends tended to decrease with the increasing silk content. Shade variation was observed on the yarns at different blend ratios. This was expected to be caused by the different physical nature of Eri silk and cotton fibres. Consequently, the dye uptake and visual shade of each dye on the two fibres were different.     

Photofading of reactive dyes on silk and cotton: effect of dye—fibre interactions

Fading characteristics of selected bifunctional and monofunctional reactive dyes have been studied on silk and cotton. Dyes were applied in the reactive and hydrolysed forms in order to study the influence of covalent bonding on the photofading of reactive dyes. The active dye-fibre interaction was found to influence the light fastness of dyes. Reactive dyes forming covalent bonds exhibited better fastness especially on cotton. Only a slight difference in light fastness of fixed and unfixed dyes was observed in the case of silk. The bifunctional reactive dyes, due to the formation of crosslinks, maintain the integrity of the fibre particularly for short periods of light exposure.     

Physical,chemical, and dyeing properties of Bombyx mori silks grafted by 2‐hydroxyethyl methacrylate and methyl methacrylate

To obtain silk weight gain and to improve silk properties, Bombyx mori silks were grafted with either 2‐hydroxyethyl methacrylate (HEMA) or methyl methacrylate (MMA). The moisture regain of the HEMA‐grafted and MMA‐grafted silks depended on the hydrophilicity of the used monomers. The acid and alkaline resistances of the HEMA‐grafted and MMA‐grafted silks were clearly improved. Both commercial synthetic dyes, that is, acid and reactive dyes, and a natural dye extracted from turmeric, with potassium aluminum sulfate as a mordant, were used in this study. The results suggested that the dye uptake increased in the presence of poly(2‐hydroxyethyl methacrylate) or poly(methyl methacrylate) in the silk fibroin structures when acid and curcumin dyes were used. The washfastness level of the HEMA‐grafted silk dyed by acid and reactive dyes was similar to that of the degummed silk. However, the colorfastness to washing of the MMA‐grafted silk dyed by an acid dye was improved when the polymer add‐on concentration was 65%. In addition, the washfastness for both grafted silks was improved when they were dyed with natural curcumin dyestuff. The acid and alkaline perspiration fastness properties remained unchanged for the HEMA‐grafted and MMA‐grafted silks when acid, reactive, and curcumin dyes were applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Dyeing of natural and synthetic textiles in supercritical carbon dioxide with disperse reactive dyes

Polyester, nylon, silk and wool were dyed with disperse reactive dyes in supercritical carbon dioxide (scCO₂). The dyes were substituted with either vinylsulphone or dichlorotriazine reactive groups. Since earlier research showed that water, distributed over the scCO₂ and the textile, increased the colouration, experiments were done with the vinylsulphone dye with varying amounts of water in the dyeing vessel, to investigate if there is an optimum water concentration. The amounts were such, that no liquid water was present. The maximum colouration was obtained when both the scCO₂ and the textiles were saturated with water. At the saturation point, deep colours were obtained with the vinylsulphone dye for polyester, nylon, silk and wool, with fixation percentages between 70 and 92% when the dyeing time was 2 h. The positive effect of water was due to its ability to swell fibres or due to an effect of water on the reactivity of the dye–fibre system. Also the dichlorotriazine dye showed more colouration when the scCO₂ was moist. With this dye, experiments were conducted in water-saturated scCO₂, varying the pressure from 225 to 278 bar and the temperature from 100 to 116 °C. The colouration of polyester increased with pressure, the results for silk and wool were not sensitive to pressure. Increasing the temperature had no influence on the dyeing of polyester, silk and wool. The fixations on polyester, silk and wool, being between 71 and 97%, were also independent of pressure and temperature.     

Behavior of chemically modified cellulose towards dyeing. IV. Dyeability of poly(methyl vinyl pyridine)-cellulose graft copolymers before and after treatment with epichlorohydrin

Grafting of 2-methyl-5-vinyl pyridine (MVP) onto partially carboxymethylated cotton having 6 meq COOH/100 g cellulose (PCMC) was effected by a Fe²⁺-H₂O₂ redox system. Different graft yields were obtained by varying MVP concentration from 10 to 100 wt % PCMC. In a subsequent step these graft copolymers were treated with epichlorohydrin. Dyeing of untreated cotton, PCMC, PCMC grafted with MVP, and epichlorohydrin-treated poly(MVP)-PCMC graft copolymers was carried out at room temperature (27°C) for varying lengths of time (2.5–60 min) in the absence of alkali catalyst or any other additives. Three reactive dyes, Procion Red M-GS, Procion Orange Brown H-2GS, and Remazole Brilliant Blue; a direct dye, Orangé Solophényle 2RL; and an acid dye, Erio Blue Marine 2GR were used at a concentration of 2% by weight of material. It was found that none of the three reactive dyes or the acid dye interacts with untreated cotton or PCMC. In contrast, the direct dye did. PCMC grafted with MVP, on the other hand, showed a substantial extent of dye exhaustion regardless of the dye used. After-treatment of poly(MVP)-PCMC graft copolymers with epichlorohydrin significantly enhanced the extent of dye exhaustion. The latter reacted almost 100% with all the dye examined, irrespective of the graft yield, which varied from 1.6% to 63%. Dyeings for reactive dyes withstood soaping for 1 hr at boil and extraction with 50% dimethylformamide, whereas dyeings for the direct dye and the acid dye failed to do so. It is believed that the presence of pyridine moieties in the graft act as an internal, built-in catalyst for expediting the reaction of reactive dyes with cellulose hydroxyls and behave as a weak base capable of salt-linkage formation in case of the acid and direct dyes.     

活性染料及其真丝绸印染工艺探讨

研究了活性染料对丝绸进行染色和印花的工艺，提高了丝绸染色产品的色牢度、染深性、得色量和提升力。优选了酸浴法、中性浴法和碱浴法染色工艺条件以及印花工艺条件。指出一氟三嗪活性基优于一氯三嗪活性基，双活性基优于单活性基。国产活性染料应在溶解度、配套助剂、染料筛选等应用方面要加强研究。     

An innovative study on dyeing silk fabrics by modified phospholipid liposomes

Modified phospholipids from the commercial soybean lecithin were prepared via acetylation of the acetone insoluble fraction phosphatidylethanolamine. N‐Acetyl‐phosphatidylethanolamine was used to prepare liposomes for encapsulating anionic dyes (acid and reactive dyes) to be used in dyeing silk fabric. Size measurements of the liposomes showed that the maximum vesicle size was 36.61 nm for empty liposomes in comparison with 39.08 and 39.75 nm for acid dyes and 51.78 and 59.20 nm for reactive dyes. The efficiency of the micro‐encapsulated dyes to dye silk fabric has been investigated and compared with the conventional dyeing process using different parameters. It was confirmed that the acetylated acetone insoluble fraction liposome shows better encapsulation of the reactive dyes and achieves more dye uptake than the acid dyes. It was also found that fastness properties of dyed silk with micro‐encapsulated anionic dyes did not change significantly more than the conventional dyeing method. Reuse of the micro‐encapsulated dyebath produces low water pollution as the effluent is virtually colourless. As a result, the process is also economic and eco‐friendly.     

活性染料S、E、F、R值测试与配伍性能研究

本文采用活性染料特征值S，E，F，R（S-直接性值，E-吸尽值，F-固色值，R-固色速率）来评价染料的配伍性，选择双活性基型活性染料，按一定工艺处方，浸染纯棉织物，测定各染料S，E，F，R值，通过测试出的S，E，F，R值选择一些染料进行组合，拼色和研究，通过实验证明，用S，E，F，R值相近的染料拼色，染色时均匀上色。色相变化很小，而用S，E，F，R值相差大的染料拼色。染色过程中色差变化很大。染色难以控制。     

合成纤维及其混纺纤维用染料的研究 Ⅰ.用于锦纶染色的含β-羟乙基砜硫酸酯基活性分散染料

本文综合了应用于锦纶染色的弱酸性染料酸性浴上色的高竭染率,活性染料与纤维的共价键结合,分散染料在纤维上迁移、匀染、盖染性好等优点,提出一类含β-羟乙基砜硫酸酯基的活性分散染料。用分子较小的分散染料结构,以含β-羟乙基砜硫酸酯为活性基;在弱酸性浴中染色,再在弱碱性浴中与聚酰胺纤维反应成共价键结合。 合成了一系列偶氮型和蒽醌型染料。进行了合成工艺、对锦纶的染色性能以及染色锦纶的牢度等试验。并讨论了染料与聚酰胺纤维的结合 这类染料可用于锦纶66和锦纶6丝纺、弹力锦纶丝和针织品,还可用于桑丝、柞丝及其与人造丝的提花织物。这类染料在锦纶上色泽鲜艳,竭染率较高,益染性优良,耐晒、耐湿处理等牢度较好,适于各种锦纶织物的染色。这类活性分散染料,具有酸性染料、活性染料和分散染料染锦纶的主要特点。     

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.     

Functional silk fabric for detection and absorption of Zn(II)

Two reactive dyes (P1 and P2) based on salicyladehyde‐4‐amino‐benzoylhydrazone, which show high sensitivity and selectivity in sensing Zn²⁺, were synthesized and used to modify nonwoven silk fabrics. The prepared silk fabric was then characterized by IR, UV‐Vis, and fluorescence measurements. The results showed that reactive dyes were chemically reacted with silk fibers, rather than physical absorption. Moreover, compared with raw silk fabric, functional silk fabric was bestowed the properties of Zn²⁺ detection and improved absorption capacity of Zn²⁺. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43952.     

Low–temperature dyeing of real silk fabrics with liquid sulphur dyes

The dyeing of silk fabric with liquid sulphur dyes has been investigated. The results show the dyeings with good exhaustion and colour fastness are theoretically possible. Under weakly alkaline, low–temperature dyeing conditions damage to silk fabric was slight.     

A new approach to the dyeing of silk with sulphatoethylsulphone dyes

A new approach to the dyeing of silk with sulphatoethylsulphone dyes, based on ß-elimination before dyeing, has been investigated. Some factors affecting both (β-elimination and dyeing have been studied. The improved dyeing process shows a high degree of dyebath exhaustion and excellent fixation in the absence of salt, thus reducing the risk of environmental pollution from salt and dyes.     

Synthesis and salt‐free dyeing characteristics of cationic reactive dyes containing polyetheramine segments

A series of cationic reactive dyes containing both quaternary ammonium and polyetheramine as soluble groups and monochlorotriazine as a reactive group have been synthesised and applied to cellulose fibre by salt‐free exhaust dyeing. Investigation of the synthesis method and dyeing properties of these cationic reactive dyes showed that the best pH value for these dyes is 6, and also that these cationic reactive dyes give a high substantivity to cellulose. In the salt‐free dyeing process, their adsorption was consistent with the Langmuir isotherm during the primary exhaustion stage, but in the secondary exhaustion stage the adsorption was in accordance with the Freundlich isotherm, and their secondary exhaustion reached up to 96% and above. Moreover, the degree of fixation, the levelling, and the transfer properties on cotton fabric were good. Light fastness reached grade 5–6, washing, perspiration, and dry rubbing fastness reached grade 4 and above, but wet rubbing fastness reached only grade 3–4.     

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.