Relationship between the solubility of disperse dyes and the equilibrium dye adsorption in supercritical fluid dyeing

In order to understand the dyeing behaviour of synthetic fibres in supercritical carbon dioxide, the solubility of some disperse dyes in supercritical fluid, as well as the rate of dyeing and the equilibrium adsorption of these dyes, have been studied. Dye solubility was measured by a dynamic analytic method at a range of pressure (7.5–25 MPa) and temperature (50–145 °C). The apparent rate of dyeing was measured and the dyeing isotherm was obtained by plotting the equilibrium dye adsorption against the equilibrium dyebath concentration. Linear isotherms were obtained when poly(ethylene terephthalate) samples were dyed with the disperse dyes. The mechanism of dyeing using supercritical carbon dioxide was discussed by considering the solubility, the dyeing rate and the dyeing isotherm.     

Diffusion of disperse dyes into super-microfibres

The disperse dyeing process for polyester fibres is complex. It is characterised by the diffusion-controlled sorption of dyes and depends on dye concentration, dyebath temperature, dye liquor flow rate and fibre count. Moreover, the dyeing properties of super-microfibres are also quite different from those of microfibres or conventional polyester fibres. In this paper the influence of dyebath temperature, initial dye concentration and fibre count on the diffusion coefficient and the sorption isotherms has been studied. The analysis of kinetic properties has been restricted to infinite dyebath conditions. All experimental results have been compared terms of fibre count and dyebath temperature.     

The roles of elevated temperature and carriers in the dyeing of polyester fibres using disperse dyes: Part 1 fundamental aspects

This review concerns the application of disperse dyes to poly(ethylene terephthalate) (PET) fibres using aqueous immersion dyeing processes and the roles of both elevated dyeing temperatures and carriers in such dyeing systems. This part of the paper presents a review of the fundamental properties and characteristics of PET fibres, disperse dyes and dyeing accelerants. In the next part of the paper, the various theories and concepts that have been proposed to explain the promotional effects imparted by elevated dyeing temperatures and carriers to disperse dye uptake on PET and other types of fibre, are reviewed and analysed, from the viewpoints of the essential physico-chemical aspects of both the aqueous disperse dye/PET and disperse dye/carrier/PET systems. Later parts of the paper will present a mechanistic model of the disperse dye adsorption process based on dye solubility as well as a novel plasticisation model of dye diffusion.     

Adsorption behaviour of azo disperse dyes on polyurethane fibre

Adsorption isotherms of disperse dyes were measured and the surfaces of dyed polyurethane, cellulose diacetate and polylactic acid fibres were observed using a scanning electron microscope and compared. Obvious crystal growth of the dyes occurred on the surface of the polyurethane fibres. The maximum dye uptake on polyurethane fibres and the degree of crystal growth varied greatly with the dye type. Factors such as the dye affinity for the fibre, crystallisation properties and dye solubility in the dyebath affect the sorbed state of the dye on the fibre surface. A mechanism is proposed for crystal formation on the fibre surface during dyeing of polyurethane fibre with disperse dyes.     

阳离子染料可染聚酯纤维染色工艺探讨

本文用分散型阳离子黄SD-5GL、红SD-GRL、蓝SD-GSL上染阳离子可染纤维,研究了温度、保温时间、升温速率、染浴的pH值对上染率和K/S值的影响,并讨论了分散型阳离子染料和分散染料拼混对染色性能的影响。研究结果表明,三组分阳离子可染涤纶可以在常压下染色。     

芳纶1313的超高温高压染色研究

本文采用超高温高压法对芳纶1313进行染色,分别研究了染料种类和染色温度对芳纶1313纱线染色日晒牢度、K/S值及染透性等方面影响,结果发现,分散染料所染纱线的各项染色性能都比阳离子染料和还原染料好;随染色温度升高,日晒牢度、纤维表面颜色深度及其纤维染透性都得到了不同程度的改善,而纱线的断裂强度随染色温度的升高变化不大。     

Dyeing studies with hydroxyanthraquinones extracted from Indian madder. Part 2: Dyeing of nylon and polyester with nordamncanthal†

Nordamncanthal is an important constituent of the colouring matter extracted from Indian madder roots. Its dyeing properties have never been studied even though the structural characteristics closely resemble those of disperse dyes. In this study, nylon and polyester have been dyed with this colorant. Linear isotherms have been obtained, confirming that the mechanism is similar to that of disperse dyes. The dye has good affinity for both the fibres. Kinetic and thermodynamic parameters have been calculated.     

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。     

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。     

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.     

Basofil纤维分散染料染色性能研究

选择了4只蒽醌结构和2只偶氮结构的分散染料，用于Basofil纤维的染色，用0.5molHCl和DMF在高温条件下将纤维上的染料萃取完全后、染料的最大吸收峰不变：在染色达到平衡时，测定了纤维上染料的浓度，结果显示：分子结构小、具有共平面的蒽醌染料适合上染Basofil纤维。染料的扩散系数和扩散活化能随染色温度上升而明显增加，其中C.I.Disperse Blue 56在纤维中扩散速度最快实验结果表明：染料的分子结构越小，染料上染量越大，扩散系数和扩散活化能的研究也揭示了相同的规律.     

Compatibility of a disperse dye mixture in supercritical carbon dioxide dyeing

The compatibility of three disperse dyes, CI Disperse Orange 30, CI Disperse Red 167 and CI Disperse Blue 79, which are commonly used as a trichromatic combination for conventional dyeing, was studied in supercritical carbon dioxide dyeing. Both the dyeing rate and the build‐up of the selected dyes were measured. Experimental results showed that they were quite compatible. The dyeings of a binary combination (CI Disperse Orange 30 and CI Disperse Blue 79, mass ratio 1:1) and a ternary combination (CI Disperse Orange 30, CI Disperse Red 167 and CI Disperse Blue 79, mass ratio 1:1:1) at different dye concentrations showed an on‐tone uptake and presented the same metric hue angles. This proved that the selected dyes could form a useful trichromatic combination in supercritical carbon dioxide dyeing. Furthermore, the uptake and exhaustion of the single dyes in supercritical carbon dioxide dyeing were similar to those in aqueous dyeing, implying that the dyeing media play only a minor role in the dyeing of polyester fibres with disperse dyes.     

Study of the dyeing properties of saffron and ultrafiltrated saffron powders,as colourants for natural and synthetic fibres

There is a noticeable growing interest in the use of natural dyes in contemporary textile dyeing, motivated by the requirements imposed, in favour of environmental prosperity. The use of natural dyes reduces significantly both the energy requirements and the environmental impact of the process. In the present work natural and synthetic fibres were dyed with the dyestuff isolated from Crocus sativus L., after aqueous extraction of the dried stigmas of the plant. Additionally, part of the powder was purified by using ultrafiltration technology. The saffron extract and the ultrafiltrated saffron retentate were used to dye cotton, wool, nylon and polyester, in various depths of shade and temperatures. Both saffron and ultrafiltrated saffron successfully dyed not only the natural substrates, but also the synthetic ones, while higher dyeing temperatures produced level dyeing with all substrates used. Ultrafiltrated saffron powder produced brighter and much stronger dyeing to the original saffron powder, due to the elimination of extraction by-products. Isothermal adsorptions for both colourants were performed on all substrates in order to investigate their adsorption mechanism. It was found that saffron and ultrafiltrated saffron follow a Freundlich-type adsorption isotherm on cotton, wool and nylon which is a typical mechanism for a planar-directed dye of big molecular weight. Nernst-type adsorption was found to occur on polyester which again is typical for the adsorption of disperse dyes on polyester. Thus, saffron can be claimed as a universal dye, able to successfully dye natural and synthetic substrates.     

涤纶常压染色促染剂的制备及应用

以有机碱三乙醇胺为催化剂,邻苯二甲酸酐(简称苯酐)与自制阳离子改性剂WLS反应,制备苯酯助剂,并将其作为涤纶分散黑ECT染料常压染色的促染剂。通过系统研究,优化出苯酯合成工艺,并探讨苯酯助剂与N-正丁基邻苯二甲酰亚胺(简称亚胺)复配对分散黑ECT常压染色性能的影响。结果表明:苯酯与亚胺有很好的协同效应,二者质量比按2∶1复配时,可获得最佳染色效果。该复配促染剂应用于涤纶常压染色中,染色后织物先进行195℃焙烘2.5 min,再还原清洗,织物的染色深度K/S值和上染百分率较常压无助剂、同条件染色工艺显著提高,而且基本达到传统高温高压的染色效果。     

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.     

Low‐temperature carrier dyeing of poly(vinyl chloride) fibers with disperse dyes

The effects of various carriers on the color yield of poly(vinyl chloride) (PVC) filaments in a disperse dyeing system were investigated. The dyeability of disperse dyes on PVC fiber was improved using appropriate carriers. The enhancement of dye uptake imparted by carriers coincided with the reduction in glass‐transition temperature, which in turn coincided approximately with the similarity of the inorganic/organic ratio values between PVC fibers and carriers. The results clearly demonstrate that hydrophobic carriers function as diluents of PVC fiber, facilitating dye diffusion by increasing segmental mobility of the fiber. The dyed PVC filaments with disperse dyes showed reasonable levels of build‐up and color fastness properties in the carrier‐assisted dyeing. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3896–3904, 2003     

Effect of microencapsulation on dyeing behaviors of disperse dyes without auxiliary solubilization

Microencapsulated disperse dye can be used to dye hydrophobic fabric in the absence of auxiliaries and without reduction clearing. However, little available information for dyeing practice is provided with respect to the effect of microencapsulation on the dyeing behaviors of disperse dyes. In this research, disperse dyes were microencapsulated under different conditions. The dyeing behaviors and dyeing kinetic parameters of microencapsulated disperse dye on PET fiber, e.g., dyeing curves, build up properties, equilibrium adsorption capacity C_∞, dyeing rate constant K, half dyeing time t_1/2, and diffusion coefficient D were investigated without auxiliary solubilization and compared with those of commercial disperse dyes with auxiliary solubilization. The results show that the dyeing behaviors of disperse dye are influenced greatly by microencapsulation. The diffusion of disperse dyes from microcapsule onto fibers can be adjusted by the reactivity of shell materials and mass ratios of core to shell. The disparity of diffusibility between two disperse dyes can be reduced by microencapsulation. In addition, the microencapsulation improves the utilization of disperse dyes due to no auxiliary solubilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dyeing properties of cotton fibres treated with liquid ammonia

Both scoured and sodium hydroxide mercerised cotton fibres have been treated with liquid ammonia atndash33.4°C using commercial operating equipment and then the ammonia removed at 130°C in a hot drum. The moisture regain and water absorbency of the fibres treated with liquid ammonia were increased compared with values on untreated fibres, whereas both these parameters on mercerised cotton fibres were decreased by subsequent liquid ammonia treatment. The fibres were dyed with CI Direct Red 2 and CI Direct Blue 1. Liquid ammonia treatment of the scoured cotton fibres increased the rate of dyeing, equilibrium dye adsorption, standard affinity, heat of dyeing and change of entropy, while the dyeing properties of mercerised cotton were adversely affected by subsequent liquid ammonia treatment.     

Dyeing nylon-6,6 with some hydrophobic reactive dyes by supercritical processing

Nylon-6,6 fibers, spun from the polyamide (polyhexamethylene diamine adipate), are increasingly required to be dyed with high washing fastness. Nylon-6,6 were dyed with hydrophobic reactive dyes synthesized in our laboratory, using supercritical carbon dioxide as the solvent system. Structures of four hydrophobic reactive dyes and their covalent force with nylon-6,6 fibers were confirmed by FTIR, MS and NMR analysis. Nylon-6,6 were also dyed with C.I. disperse red 2 to compare the result with specimen dyed by hydrophobic reactive yellowish red dye (dye I), which further demonstrated that covalent force was formed between dye-fiber interaction. Dye uptake was moderate to good and the dyed fabrics had very good fastness properties. Results of the latter studies indicated that dyeing nylon-6,6 in supercritical carbon dioxide is feasible.     

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.