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.     

The Potential of Surfactant Modified Supercritical Fluids for Dissolving Polar Dyes

The solubility of different polar dyes in supercritical carbon dioxide and ethane (scCO₂ and scC₂H₆), both modified and unmodified with various surfactants and solvents was determined at temperatures from 323–373 K and in pressure range from 10–45 MPa. The solubility data were correlated with some empirical equations. Furthermore, dyeing experiments with wool and cotton dyes were conducted in order to characterize the impact of modifiers on the dyeing procedure and coloring properties and to prove the practicability of modified fluid systems for commercial procedures.     

Aftertreatment of polyester fabric dyed with temporarily solubilised disperse dyes

Temporarily solubilised disperse dyes derived from aminophenyl-4-(β-sulphatoethylsulphone) are exhausted on the polyester fibre mostly in the vinylsulphone form and to a lesser extent as their hydroxyethylsulphone analogues. After dyeing, to remove the unexhausted dyes on the polyester fibre, sulphite anions were added to the dyebath. The vinylsulphone residue of the dye was attacked by the sulphite anion via an addition reaction converting the dye into a soluble derivative, which then had little affinity for the polyester fibre. The effect of sodium sulphite on the conversion of the dye was investigated using HPLC. The wash and rub fastness properties of the dyed fabric aftertreated with sodium sulphite were similar to those obtained with reduction clearing.     

The role of vinylsulphonyl reactive dyes in prevention of wool damage

Reactive dyes of the vinylsulphone and α-bromoacrylamido types inhibit wool fibre degradation during dyeing. The effect is proportional to the amount of dye applied, which may be explained in terms of set inhibition and modification of the cell membrane complex. Reactive dyes are capable of interfering with the fibre thiol-disulphide interchange reactions, as evidenced by a study of model thiol derivatives of vinylsulphone dyes. H.p.l.c. has been widely employed to separate and assist with identification of these thiol adducts. The role of the cell membrane complex has been clarified using reactive vinylsulphone fluorescent compounds as dye models and following fibre penetration using fluorescence microscopy.     

A significant approach to dye cotton in supercritical carbon dioxide with fluorotriazine reactive dyes

A series of fluorotriazine reactive dyes have been synthesized and applied to dye cotton in supercritical carbon dioxide (scCO₂) with good dyeing results. The pieces of cotton to be dyed were previously presoaked in a protic solvent and cosolvents were applied during dyeing. The colour strength of the dyeings was evaluated by K/S measurements. The K/S values achieved on cotton dyed were up to 35.8 ± 4.2. Even after the cotton was subjected to a Shoxlet extraction at 358 K for 1 h, a maximum K/S value of 20.2 ± 1.8 was measured. The percentage of dye molecules chemically fixed to the cotton was on average 85%. The excellent reactivity of fluorotriazines allowed a reduction of 3 h on the dyeing time. It is noticeable that a dye concentration of 10% on weight of the fibre (owf) can be applied to dye cotton with fluorotriazines, since no damage of the cotton fibres occurred, as observed for the chlorotriazines at this high dye concentration.Dyes with fluorotriazine as reactive group were found to be the most preferable dyes for dyeing cotton in scCO₂, as they were able to exceed the limitation of the reaction with the cotton.     

Chemical modification of nylon 6 and polyester fabrics by ozone‐gas treatment

In a previous article, we reported on the ozone‐gas treatment of wool and silk fabrics in relation to the gas‐phase processing of textile fabrics. The treatment incorporated an oxygen element into the fiber surface and contributed to an increase in water penetration into the fabric. In this study, nylon 6 and polyester fabrics were treated with ozone gas in the same way as that of the wool and silk fabrics. The treatment incorporated much more oxygen into the fiber surface in the form of ? COH and ? COOH, as shown by electron spectroscopy for chemical analysis. Water penetration increased considerably with treatment, and the apparent dyeing rate and equilibrium dye uptake were also improved, especially for the polyester fabric, despite an increase in the crystallinity. Therefore, it seemed that the treatment brought about a change not only in the fiber surface but also in the internal structure of the fibers (the crystalline and amorphous regions) with regard to the dyeing behavior. Further, the mechanical characteristics of the ozone‐gas‐treated polyester and nylon 6 fabrics were measured with a Kawabata evaluation system apparatus. The shearing modulus and hysteresis widths increased with treatment, especially for the polyester fabric. Therefore, it was clear that the treatment caused a change in the fabric hand to crisp. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1344–1348, 2006     

Dyeing transition temperature of wools treated with low temperature plasma,liquid ammonia,and high‐pressure steam in dyeing with acid and disperse dyes

Wool fibers treated with oxygen low‐temperature plasma, liquid ammonia (NH₃), and high‐pressure (HP) steam were dyed with two acid and three disperse dyes. Rate of dyeing, saturation dye uptake, and dyeing transition temperature were measured. Rate of dyeing of the O₂ plasma, NH₃, and HP steam‐treated wools increased with acid dyes, whereas it did not increase with disperse dyes. Although dyeing transition temperature for acid dyes was decreased by the plasma, NH₃, and HP steam treatments, the temperature for disperse dyes was not changed by the treatments. Therefore, it seems that acid dyes penetrate by the intercellular diffusion through the interscale Cell Membrane Complex (CMC) of wool, whereas disperse dyes penetrate by the intracellular diffusion through the intrascale cuticle surface independently with CMC relaxation by the treatments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1058–1062, 2001     

Polymerizable Dyes Part II

Abstract

Arylene bisazo resorcinol dyes IIIa-e were prepared and polycondensed with formaldehyde in the presence of aqueous oxalic acid. The resulting polymeric dyes IVa-e were characterized by yield, melting point, colour, elemental analysis and visible and IR spectroscopy. The thermal properties of polymeric dyes were examined by thermogravimetric analysis. Their dyeing performance on nylon and polyester was assessed. The dyeing on nylon and polyester had yellow, orange, red and brown shades with moderate to good, light and wash fastness. Polymerization of bisazo dyes IIIa-e with formaldehyde on dyed nylon and polyester have also been carried out. The dyeing properties of polymeric dyes were compared with the dyes polymerized on nylon and polyester.     

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 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.     

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.     

Dyeing properties of oxygen low-temperature plasma-treated wool and nylon 6 fibres with acid and basic dyes

Wool and nylon 6 fibres treated with oxygen low-temperature plasma were dyed with acid and basic dyes. Despite the increase of electronegativity of the fibre surface caused by the plasma treatment, the rate of dyeing of wool was increased with both dyes, while that of nylon 6 was decreased with the acid dye and increased with the basic dye.     

Yellow pigment of Metarhizium anisopliae and its application to the dyeing of fabrics

Microbial dyes have received substantial attention because of their natural environmental protection, simple access, and reduced regional and seasonal restriction. In this work, a microbial dye, the yellow pigment produced by Metarhizium anisopliae, was first studied then applied. The strain produced by the culture was identified, and the conditions for producing yellow pigment were optimised. Further, the stability of M. anisopliae yellow pigment was examined, and the pigment was applied to the dyeing of silk and wool fabrics. The results showed that the homology of the strain with M. anisopliae was 99.98%. In liquid fermentation culture, the optimal carbon source was glucose, and the dosage was 30 g/l. The maximum pigment yield can be obtained by culturing with 4% v/v of inoculation quantity at pH 7 and 30 °C. In addition, the effects of pH, temperature and metal ions on the yellow pigment of M. anisopliae were significant. The optimum dyeing process conditions were dyeing temperatures of 80 °C for silk and 90 °C for wool, with a dyeing time of 60 min. This research developed a novel microbial dye and studied its application for the dyeing of protein fibres.     

Study of the Influence of Gemini Cationic Surfactants on the Dyeing and Fastness Properties of Polyester Fabrics Using Naphthalimide Dyes

In this paper, the dyeing and fastness properties of three monoazo naphthalimide dyes including different imide groups (dye 1: ethyl amine, dye 2: ethyl glycinate and dye 3: glycine) on a polyester fabric were investigated in the presence of two gemini cationic surfactants (symbolized as 12‐4‐12 or 14‐4‐14) and a conventional single chain surfactant, dodecyltrimethylammonium bromide (DTAB). The color strength (K/S) of naphthalimide dyes on polyester fabric was measured through the reflectance spectrophotometric method, and the values obtained in the presence of different cationic surfactants increased in the order of dye 3 < dye 2 < dye 1. Although the K/S values indicated that the gemini cationic surfactants had almost no effect on the dyeing behavior of dye 1, but they were effective in dyeing ability of dye 2 and dye 3. The data for dye 2 demonstrated that build up of polyester fabrics in the presence of gemini surfactants are more than the conventional cationic surfactant, and also K/S values of dye 3 on polyester fabrics were in the order: DTAB > 12‐4‐12 > 14‐4‐14. It was found that the washing and rubbing fastness properties improved with increasing the concentration of surfactants. In addition, the sublimation fastness of dye 3 was more than the other dyes owing to the presence of a polar group in its chemical structure, and the light fastness of naphthalimide dyes on polyester fabrics was generally moderate.     

Effects of lugworm protease on the dyeing properties of protein fibers

A lugworm protease, Perinereis aibuhitensis, was used to improve the dyeing properties of protein fibers such as wool and silk. The optimal condition for the activity of the lugworm protease was about 40 °C at pH 7. The wool and silk were treated with the protease extracted from a lugworm and the K/S values of the dyed wool and silk were measured using a spectrophotometer in order to compare the dye uptake. The protease treatment enhanced the dyeing properties of protein fibers without severe changes in their mechanical properties. The surface appearances of protease-treated fibers were observed via microscopy.     

Disperse dyeing of polyester fibers: Kinetic and equilibrium study

The effect of temperature on the dyeing rate constant k, diffusion coefficient D, and time of half‐dyeing t_1/2 was evaluated for the dyeing of polyester fibers with two disperse dyes, an azo and an anthraquinone dye. Activation energies of diffusion E were calculated. The polyester dyeing equilibrium was also studied and the partition coefficient K and standard affinity Δμ° at various temperatures were determined for the anthraquinone dye. Standard enthalpy ΔH° and standard entropy ΔS° of dyeing were also obtained. The same equilibrium parameters were not obtained for the azo dye because of its dyeing behavior. A similar kinetic and equilibrium study was made for the pure azo and anthraquinone compounds free from the dispersing agents present in the commercial dyes and the results are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 123–128, 2002     

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).     

Alternatives to Water in Textile Processing

Attempts have been made to correlate the use of organic solvents as alternatives to water in textile processing with the ‘solubility parameter’ concept. Chlorinated hydrocarbons prove suitable for scouring and some finishing operations since their solubility parameters are ideal for such operations. In dyeing, however, the solubility parameter of polyester fibres, dyes and perchloroethylene are very similar, resulting in poor exhaustion of conventional disperse dyes. New solvent dyeing systems and new dyes, with high partition coefficients in polyester fibres, must be developed for solvent dyeing to become of practical consideration. Other solvents have been examined for solvent assisted dyeing. It has been shown that when benzyl alcohol and 2-phenoxy ethanol are used in dyebaths at concentrations at which these solvents are not completely in solution, both the rate of dyeing and penetration of dye into the fibre can be markedly increased in comparison to normal aqueous dyeing with polyester, nylon and acrylic fibres.     

The Dyeing of Wool–Polyester Blends with Reactive Disperse Dyes

The dyeing behaviour of the Procinyl (ICI) range of reactive disperse dyes on wool–polyester blends is described. Two of the dyes were found to dye both components of such blends to approximately the same depth, whilst the remaining three dyes in the range strongly favoured the wool component.     

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.