Coloration Technology最新文献

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.

Doping with metal elements is a valid way to alter the electrochromic performance of single materials. The doped metal ions can modify the electronic structure of the pristine materials, this results in a change in the transfer and migration of electrons or ions in electrochromic reactions. In this work, a series of copper (Cu)-doped titanium dioxide (TiO₂) films (0.5%, 1% and 5 wt%) were fabricated by a hydrothermal method and a subsequently spin-coated approach. The effects of doped Cu on the morphological structure, crystallinity, elemental chemical state and electrochromic properties of TiO₂ films were evaluated by field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical techniques. The doping of Cu into TiO₂ exerts a substantial influence on its crystal structure, with a marked deterioration in crystallinity observed as the doping concentration increases. The results show that the ionic diffusion coefficient of the 0.5% Cu-TiO₂ film is 7.74 × 10⁻¹⁰ cm²/s, the light modulation range is as high as 50.3%, the bleaching and colouring switching times are 1.95 and 16.43 s, respectively, and the light transmittance retention rate can be maintained after 200 cycles. Overall exhibits preferred electrochromic and electrochemical properties. This study indicates that Cu doping with moderate concentration is a feasible way to heighten the electrochromic property of TiO₂.

A non-destructive, user-friendly, portable colour measurement system was developed using the MATLAB interface that gives acceptable results with any imaging sensor. Digital images captured by the imaging sensor were used to obtain quantitative colour information in three formats, namely, RGB, XYZ and CIELAB. The zoom-in feature is useful for obtaining detailed colour features of the image, while cropping of the region of interest aids in reducing the image matrix and, ultimately, the computational power required. Quantitative information on the colour value of the product (both average and region to region) can be obtained in all three formats (i.e., RGB, XYZ and CIELAB). It also gives the three closest Royal Horticultural Society (RHS) values of the product. The accuracy of the measurement system was first validated against a standard colour chart then it was tested using three image sensors of different configurations. Coefficient of determination (R²) and root mean square error values of 0.983 and 3.391 for L*, 0.994 and 1.851 for a* and 0.996 and 2.042 for b*, respectively, were obtained during performance evaluation. Similarly, when different imaging sensors were used for colour determination, the colour values showed no significant variation for all tested samples (i.e., various fruits and vegetables of different chroma/hues).

Fabric detection in the materials industry plays a vital role in the global economy, making effective quality control measures essential to ensure product value and reduce manufacturing waste. With the rise of Industry 4.0, manufacturing companies have been striving to develop automated fabric defect detection systems to overcome the limitations of traditional manual inspection. However, because of challenges in creating highly effective fabric defect detection methods with strong noise resistance, conventional systems often struggle to capture intricate fabric details and accurately distinguish between defect types. To address these challenges, this research introduces an innovative approach called the Enhanced Deep Stacked capsNet Ensemble Gazelle Neural Network (EDSEGNN) for multi-level local and global defect classification. By incorporating the Window-aware Guided Image Filtering technique, image quality and resolution are enhanced, enabling the detection of fine fabric details. Additionally, the Wavelet Packet Transform aids in segmenting fabric defects by identifying small patterns through varying frequency waves. In the final stage, the EDSEGNN model performs local defect identification and multi-level global defect classification, distinguishing between normal and defective patterns while categorising defect types like discoloration, stains, foreign objects, cuts, holes, thread issues and metal contamination. The proposed method achieves impressive results, with a peak accuracy of 99.8%, along with high recall (99.5%) and F1-score (99%), compared with existing methods. The proposed approach offers a highly accurate and robust solution to the challenges faced by traditional fabric defect detection systems, representing a valuable advance in automated quality control for the materials industry.

Anthraquinone dyes are known for their significant colour (brightness of shade in the red, blue and green areas) and light fastness properties compared with other synthetic dyes (such as azo-based dyes). However, challenging multi-step synthesis of anthraquinones and limited access to fewer substituents result in insufficient reactivity, hindering their wider industrial applications. Therefore, seeking highly substituted anthraquinone-based colourants from natural sources is gaining interest among researchers. Notably, certain species of Dermocybe mushrooms are recognised for their red gills rich in anthraquinone colourants, which have been studied. However, limited knowledge of the chemotaxonomic characteristics of their species and molecular structure hinders wide use of their commercial applications. Our study screened extraction methods for their selectivity towards specific anthraquinone types, such as glycosidic vs non-glycosidic, or those with carboxylic acid groups vs those without. In our observation, a sequential extraction strategy, starting with aqueous buffer extract followed by acetone extract, selectively yielded carboxylic acid-containing anthraquinones and non-carboxylic acid-containing anthraquinones, respectively. We carried out a detailed analysis of anthraquinone-based colourants in Cortinarius semisanguineus, comparing MS¹-MS² profiles with two other species of the Dermocybe fungus group (Cortinarius sanguineus and Cortinarius ominosus), highlighting key interspecies differences in expressing certain anthraquinones or regioisomers. This study led to the structural identification of eleven natural anthraquinones and their glycosidic forms among these species. The carboxylic anthraquinones identified and characterised by their fragmentation pattern using MS¹-MS² profiles include dermolutein, dermorubin, chlorodermorubin, endocrocin and chlorodermolutein, while the non-carboxylic anthraquinones, primarily from the acetone extract, were dermoglaucin, emodin and dermocybin.

In this study, the dyeing properties of atmospheric plasma and tannic acid surface modified ultra-high molecular weight polyethylene fabric were examined. The study focused on optimisation of colour strength. The effect of plasma treatment time and discharge power on colour strength was optimised. Dyeing parameters were optimised by running central composite response surface design of experiments. After dyeing, surface characteristics were observed by K/S (colour strength), colour fastness to soaping, scanning electron microscopy (SEM) and X-ray dispersive spectroscopy (XDS), Fourier Transform–infrared (FTIR) spectroscopy, rubbing fastness and contact angles, respectively. The response surface experimental design results showed better colour strength by reducing padder pressure and increasing the curing temperature and curing time. SEM showed increased roughness of surface and tannic acid adhesion to the surface. Both XDS and FTIR spectroscopy showed increased surface polarity. Enhanced durability was displayed at 1000 W for 20 seconds of exposure and 1% TA-$��{\mathrm{Na}}^{+}�$ (w/v) for 6 hours at pH 4-5. Contact angles showed enhanced hydrophilic behaviour. Also, the rubbing fastness was good. The process had a low cost. This approach was suitable because of the higher production rate of continuous dyeing, and it was also sustainable, considering that tannic acid is a natural resource and atmospheric plasma is a waterless treatment.

The textile sector has been the subject of research aimed at discovering more sustainable alternatives to harmful chemicals, and coloration technologies. In this study, the colouristic capacity of the natural annatto dye was evaluated in 100% polyester (PES) fabrics and in 100% PES fabrics with recycled thread. A comparative characterisation of a dye extracted directly from annatto seeds with a commercial natural dye was also carried out. The dyeing processes were conducted with the commercial natural dye at temperatures of 105, 110 and 115°C and pH levels of 4, 4.5 and 5, following a 2² full experimental design including two axial points and triplicate in the central point. The dyed fabric samples were subjected to wash fastness and dry and wet rubbing tests, to evaluate colour quality. The results were analysed using Statistica software, and the 100% PES fabric samples with the best exhaustion values (91.9%), colour intensity (K/S) values (1.44) and satisfactory fastness values were dyed at a temperature of 117°C and pH of 4.5. Furthermore, samples with recycled PES yarn were dyed and compared with conventional PES yarn, demonstrating similar dye and fastness characteristics, as well as intense coloration.

This study introduces an innovative recurrent neural network called long short-term memory (LSTM) as a prediction model, which is used to predict angle-dependent reflectance distributions of colour samples with glossy and matte surfaces. A two-dimensional (2D) reflectance measurement system was developed to measure the angle-dependent reflectance in this study. Its structure mainly included a semicircular rotating mechanism, a high-resolution digital camera and a high-quality white light-emitting diode. A semicircular rotating mechanism was designed to rotate from 10° to 170° in the vertical direction. Two ColorGauge miniaturised colour charts with glossy and matte surfaces were selected as test chips. The test chips on ColorGauge miniaturised colour charts included fives colours of glossy white, glossy black, matte red, matte green and matte blue. The reflectance distributions of the test chips were measured by the 2D reflectance measurement system, and the measured reflectance data were used as training data in the LSTM model. In comparison with second- and third-order regressions, the mean CIE lightness difference (0.09) using the LSTM model was lower. Therefore, it was verified that the LSTM model performed well in predicting reflectance distributions. In addition, the LSTM model was also validated on the additional test samples (10 matte chromatic samples and five glossy achromatic samples). The maximum and minimum mean CIE lightness differences were 3.77 and 0.64 for matte chromatic samples, and 2.34 and 0.42 for glossy achromatic samples, respectively. The results of small prediction errors indicated that the LSTM model presents excellent prediction performance.

This study explores the use of dyes extracted from Berberis aristata and Bistorta amplexicaulis for dyeing pashmina fabric. The effectiveness of these plant-derived dyes was evaluated based on colour strength, absorption efficiency and fastness properties including washing, light and rubbing. Results indicate that both Berberis aristata and Bistorta amplexicaulis dyes significantly enhance the colour quality of pashmina fabric, with simultaneous mordanting yielding the highest colour strength and fastness properties, followed by premordanting. Berberis aristata exhibited poor light fastness (1), but showed excellent rubbing and washing fastness (5), while Bistorta amplexicaulis demonstrated good light fastness (4) and (4/5), as well as excellent performance in rubbing and washing fastness (5). Dye concentrations positively impacted colour strength, with higher concentrations resulting in deeper shades. The percentage absorption of the dye into the fabric was notably high, reflecting effective dye uptake. Mordant enhanced the colour quality of the fabric because of the increased efficiency in absorption, colour strength, colour coordinates and fastness grades in terms of washing, light and rubbing, respectively. These findings suggest that dyes from Berberis aristata and Bistorta amplexicaulis are promising for textile applications, offering vibrant, durable colours and adaptable dyeing methods.

To expand the colour change range of thermochromic materials, two types of thermochromic microcapsules (TCMs) with different colour change temperatures and effects were utilised to prepare a TCMs blending system exhibiting a three-stage colour transition at temperatures ranging from 10 to 60°C. Thermochromic paints were then prepared based on this TCMs blending system using a modified waterborne polyurethane (WPU). The thermochromic properties of the TCMs blending system and the impact of crosslinking modification on the coating properties were investigated. The findings revealed that the ratio of TCMs influences the colour change effect and temperature of the blending system. With temperature variations, the colour of the TCMs blending system can reversibly transition between blue, green and yellow, offering a more vibrant thermochromic effect compared with conventional thermochromic materials. The modified WPU enabled the preparation of paint from the blending system, which was applied to fabric surfaces to create multistage thermochromic fabrics. The mechanical properties, water resistance and adhesion of the modified coating were enhanced, and the colour fastness to washing of the fabrics improved by two grades. This study has practical significance for the application of TCMs and the development of colour-changing textiles.