Coloration Technology最新文献

Coloration using soil-based dyes is a fast-growing subject of enquiry in fibres and textile surface design, with pigments and microbes involved in their production being extensively researched. Dyeing techniques using this rich natural resource have also been integral to long-standing textile traditions worldwide. Grounded in an anthropological study of the dyeing practice of Marka-Dafing hunters in Burkina Faso, West Africa, this paper presents an analysis of the coloration processes in vouwo, or mud dye, used for hunting and ceremonial garments. It highlights complex biochemical and microbiological reactions occurring in a dyeing experiment curated by dyers throughout an 18-month-long fermentation process. The authors propose an interdisciplinary approach to the study of vouwo that combines (i) detailed examination and documentation of craft practice with (ii) a materials science-based analysis of the iron ore used and of the resulting brown colour shades and (iii) a microbiological description of the multiple roles of bacteria and their complex interactions with plants such as Acacia nilotica in the dyeing process. By underlining the material, biochemical, microbiological and medicinal properties of vouwo dye, our study of dyeing with soil as a natural colourant calls attention to a potential role of traditional craft knowledge in dialogue with modern science for the future production of more sustainable and health-promoting dyes.

This study aims to optimise the dyeing process of cotton fabrics using Mexican cochineal (Dactylopius coccus Costa). The objective is to obtain purple hues through the design of experiments and by using multivariate analysis. Plackett–Burman experimental designs and the response surface method were used to systematically optimise the dyeing parameters. The meta-mordanting process was the most critical factor affecting the achievement of purple hues, followed by cochineal concentration, toner concentration and dyeing time. The multivariate analysis of principal component analysis with discriminant analysis was applied to determine the significance of washing methods and toner types. Various traditional Mexican toners, including tequesquite, cardon and ash, were evaluated. The washing method was not significant, while the toner type showed a tendency towards clustering, indicating a significant effect on the dyeing process. The most recommended method was the one using tequesquite, with 20% on weight of fabric (owf) cochineal, 5% owf toner and a dyeing time of 66 minutes. Cardon was recommended as a viable toner alternative. This research provides a reproducible method for achieving desired purple shades, preserving traditional dyeing techniques from Mexican indigenous cultures.

Polyaniline (PANI) composite is an effective way to improve the electrochromic properties of inorganic materials. However, there is still a lack of systematic research on the electrochromic properties of PANI composite titanium dioxide (TiO₂) materials. In this work, TiO₂ thin films with different PANI composite contents (PANI-TiO₂) were prepared by deposition method combined with hydrothermal method. The effects of different composite contents of PANI on the morphology and electrochromic properties of the samples were investigated using X-ray diffraction (XRD), Raman, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM) and electrochemical methods. It was found that a certain amount of PANI composite could enhance the electrochromic properties of TiO₂ electrochromic materials. In this study, the 5% PANI-TiO₂ film has the best electrochromic performance, the ion diffusion coefficient of 5% PANI-TiO₂ composite film is 7.42 × 10⁻¹⁰ cm²/s, the optical modulation increased by 54.2%, and the bleached and coloured switching time are 19.98 and 33.45 s, respectively, which all indicate that the appropriate amount of PANI composite can enhance the electrochromic performance of TiO₂ materials. These results show that the appropriate amount of PANI composite is indeed as an effective way to optimise the electrochromic performance of TiO₂.

Previously published data reported for the temperature dependency of the diffusion of an organic acid within PA 6 film, as well as the desorption of three acid dyes from dyed nylon 66 fabric, diffusion of an acid dye within nylon 6 film and the adsorption of a sulphur dye onto nylon 66 fabric, over a diverse range of application/washing/dyeing temperatures and conditions, were re-evaluated using the Williams-Landel-Ferry (WLF) equation. As the experimentally observed diffusion/desorption/adsorption of the organic acid, each of the anionic dyes and the sulphur dye within/from/onto each of the respective polyamide substrates adhered to a WLF relationship, the thermally activated diffusivity of the various anionic species is governed by the thermally regulated structural relaxation times of the water-saturated, water-swollen, water-plasticised, poly(ε-caprolactam) or poly(hexamethylene) adipamide macromolecules. The plasticisation model of dye diffusion seems to offer a reasonable explanation of the observed temperature dependency of the diffusivity of the simple organic acid, each of the four acid dyes and the sulphur dye within both types of aliphatic polyamide.

This article details how the Colour Index™ (CI) system categorises and unambiguously labels commercial dyes and pigments based upon their chemical constitutions. It outlines the current process by which colourants that are new to the market find a place within CI and acquire generic identifiers. The contents of this paper will enable both experienced users of CI and those who are unfamiliar with the resource to gain not only a detailed understanding of its classification system, but also a deeper appreciation of what colourant designations signify and how they are correctly utilised.

The leather industry is facing increasing environmental pressure, with ongoing scrutiny of its chemical usage, processing conditions, end-of-life criteria and CO₂e footprint. This paper presents a disruptive technology that delivers a groundbreaking approach to addressing these immediate challenges for the leather industry. The patented Avicuero system provides a “green” technology enabling simultaneous tanning and dyeing, which is completely free of metals, aldehydes and bisphenols, with the resultant leather offering good hydrothermal stability combined with excellent depth of shade and colour fastness properties. Analyses of the dyeing process demonstrated excellent penetration of the leather substrate and near complete exhaustion and fixation of the reactive colourants (based on halotriazine and sulphatoethyl sulphone chemistry), leading to excellent colour strength for the Avicuero Black SL tanned leather, with superior fastness performance relative to competitive tanning technologies. In addition, the multifunctional reactive dye/collagen crosslinking imparted effective tanning to the leather with a hydrothermal shrinkage temperature of 77°C. Further technical advantages are the significant reductions in water and energy requirements (reduced machine processing time and processing temperatures) compared with current industrial technologies, and continuing to use current standard tannery processing equipment.

To investigate the effects of three commercial bleaching agents (hydrogen peroxide, sodium percarbonate and sodium hypochlorite) on textile products, the structural changes and chemical damage caused by these bleaching agents on wool fabrics were quantitatively characterised using attenuated total reflection Fourier Transform–infrared (ATR-FTIR) spectroscopy. A comparison of the spectral changes before and after the treatment showed that the wool fabrics treated with sodium hypochlorite and sodium percarbonate were severely and slightly damaged, respectively. By contrast, the fabrics treated with hydrogen peroxide were almost undamaged and whiter. Compared with untreated wools, or those treated with oxygen-bleaching agents (sodium percarbonate and hydrogen peroxide), the amide I band centred at 1647 cm⁻¹ in the ATR-FTIR spectra of the wool fabrics broadened significantly after the treatment with the chlorine-bleaching agent (sodium hypochlorite). Furthermore, the amide I band broadened, and the intensity of the amide III band centred at 1235 cm⁻¹ increased with increasing the chlorine content and yellowing in the wool fabrics. Based on these experiments, it was concluded that the structural changes and chemical damage caused by the chlorine-bleaching treatment of wool fabrics caused the oxidative cleavage of SS groups and the randomisation of cortex structures due to chlorination.

This study explores the use of lecithin during the mordanting stage in the natural dyeing of wool with purple sweet potato extract to enhance dye uptake. We investigate the impact of lecithin on dyeing efficiency, considering variables such as temperature, pH and dye concentration. The results demonstrate that incorporating lecithin during mordanting significantly improves dye uptake, resulting in a true purple hue with enhanced chroma in the dyed wool yarns. Dyeing under acidic conditions produced higher colour strength because of the prevalence of the red-coloured flavylium cation form of anthocyanins. Fourier Transform–infrared spectroscopy confirmed the presence of anthocyanins and their interactions with wool fibres. Additionally, colour fastness evaluations showed that the use of aluminium salts (Al³⁺) as a mordant played a key role in enhancing fastness properties. Light fastness was rated fair to good for both peel- and flesh-dyed wool samples. Moreover, the purple sweet potato extract demonstrated significant anti-bacterial properties, effectively inhibiting a range of bacterial strains, including both Gram-positive and Gram-negative bacteria. This study provides valuable insights into optimising natural dyeing processes and highlights the potential of lecithin in mordanting for sustainable and high-performance textile applications.

There is a growing demand in the printing industry for pigment-based inks with excellent lightfastness and rub resistance qualities. In this work, a novel ink with the formulation ethyl 2-[4-(1,3,4-oxadiazole-2(3H)-thione-5-yl)phenylhydrazono]-3-oxobutyrate (OXKT) was prepared as a pigment and its printability was investigated for use in printing. The OXKT was synthesised, characterised then printed on uncoated and gloss-coated papers and Bristol cardboard. Physical tests and spectrophotometric measurements were carried out to determine the technical characteristics of the printed ink. Additionally, print quality, ink density and gloss were evaluated. The results showed that the proposed ink with the OXKT compound had acceptable rub resistance. Also, the gloss and light fastness values exceeded the acceptable rates for the printing industry because of their colour differences. However, more research needs to be conducted to improve light performance. Nevertheless, it is still possible for use in applications that do not stipulate strict light fastness values.

Natural dyes are gaining interest as a more ecological approach to textile coloration, as well as for slow fashion and the bioeconomy. The use of local raw materials is a way of valuing small producers and recovering traditional knowledge. In this context, the current investigation was developed to study the use of lignocellulose-based Stryphnodendron adstringens (Mart.) Coville (known as “barbatimão”) bark extract, from a native tree in Brazil, as a natural dye for textile dyeing. Physical–chemical analyses were performed on the reddish-brown extract, the results of which showed an acidic pH and the likely presence of condensed tannins and flavanols. The optimised dyeing process was evaluated by a 2³ factorial design. The fabrics dyed under optimised conditions were evaluated for colour fastness to laundering, rubbing, light and perspiration, and obtained good colour fastness ratings in most of these tests. Wastewaters from dyeings were characterised by physicochemical analyses. Because of the high turbidity and high biochemical oxygen demand and chemical oxygen demand levels, as well as the amount of residual metal ions from dyeing with mordants, the need for wastewater pretreatment was evident. Based on this research, S. adstringens extracts have significant potential for textile coloration.