Application of genetic algorithm to color recipe formulation using reactive and direct dyestuffs mixtures

Color reproduction is a science in constant development. In this article, a new model to solve the color recipe prediction problem using a genetic algorithm is proposed. The objective is to optimize the color recipe prediction stage by determining the dyes to use in a mixture and their respective proportions to reproduce the target color. Two ranges of dyes were used for dyeing 100% cotton woven fabrics: three reactive dyes (CI Reactive Red 238, CI Reactive Yellow 145, and CI Reactive Blue 235) and four direct dyes (CI Direct Orange 34, CI Direct Red 227, CI Direct Blue 85, and CI Direct Black 22). The criterion of optimization, in reproducing the desired shades, is to minimize the CMC color difference between the desired reference color and the color resulting of the predicted recipe. The proposed algorithm revealed good results with small CMC color differences between target and reproduced colors. The effectiveness of the algorithm was also evaluated and proven by calculating errors between the predicted concentrations in the proposed recipes and the actual concentrations.     

粘胶纺液着色用还原染料两元拼染中性色的研究

中性色具有特殊的色彩魅力,深受人们的喜爱.但是,因为中性色多为三次色,所以在印染加工中存在拼染困难、成品色光稳定性差等缺点,这对粘胶纺液着色加工,会产生致命的影响.本文选取8种还原染料,对以"两元拼色"方式拼染中性色的可行性进行了研究.实验表明,以"两元拼色"方式,基本可以实现对中性色的色调、饱和度和明度的覆盖."两元拼色"有利于提高中性色的拼染效率和成品色光的稳定性.     

Fast algorithm for computing color gamuts

A fast and accurate algorithm for computing color gamuts has been developed. In the form presented here for illustration, color gamuts are computed from the dye amounts of subtractive color mixtures. Based on the one-to-one correspondence between dye amount space and color space, the simple four-step algorithm performs a boundary search in dye amount space and a map over to color space. Application to block dyes and commercial reversal film dyes on a desktop computer demonstrates the algorithm's validity, accuracy, applicability, and exceptional speed. © 1993 John Wiley & Sons, Inc.     

代替C.I.直接黑38的黑色直接染料的应用研究

研究了3个直接黑色染料的应用性能，与C．I．直接黑38进行了比较，结果显示：这些染料在上染曲线、染色深度、染色工艺、可见光谱和染料色光与C.I.直接黑38近似，在耐光和耐洗牢度方面相当或优于C．I．直接黑38。     

Dyeing behavior of polypropylene blend fiber. II. Ionic exchange mechanism of dyeing

The dyeability of polypropylene fibres modified by two nitrogen polymeric additives containing dye sites of different basicity and accessibility was investigated using an acid dye. The thermodynamic and kinetic parameters of dyeing under infinite bath conditions were determined for four aqueous dye solutions. It is postulated that ionized molecules of acid dyes diffuse within the fiber after activation of a dye site by a suitable agent. In addition, color yield and color fastness of various dyes have also been studied. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 543–550, 1997     

Adsorption of anionic dyes on poly(epicholorohydrin dimethylamine) modified bentonite in single and mixed dye solutions

The performance of poly(epicholorohydrin dimethylamine) modified bentonite (EPIDMA/bentonite) as an adsorbent to remove anionic dyes, namely Direct Fast Scarlet, Eosin Y and Reactive Violet K-3R, was investigated in single, binary and ternary dye systems. In adsorption experiments in single dye solutions, the adsorption of the three dyes onto EPIDMA/bentonite was described by the Langmuir isotherm model and the pseudo-second-order kinetic model. At low dosage of EPIDMA/bentonite, preferential adsorption was observed for the dye with higher affinity to the adsorbent in mixed dye systems. The reduction in uptake of the dye with increasing equilibrium dye concentration in the isotherm and desorption in the kinetic curves were observed for the dye with lower affinity. The total amount of dyes adsorbed versus the total equilibrium dye concentrations were fitted well by the Langmuir isotherm model. The kinetics of the total adsorbed amount of dyes followed the pseudo-second-order kinetic model. The effect of the dosage of adsorbent on color removal efficiency, residual color distribution and adsorption kinetics was investigated.     

彩色光刻胶用蒽醌染料的合成及稳定性研究

为实现彩色滤光片更高分辨率的发展需求，作为关键原材料的彩色光刻胶着色剂从颜料向染料体系转变是重要的趋势。然而染料分子的光热稳定性较差，亟需从分子结构方面探索提升稳定性的有效策略。以1,4,9,10-蒽四醇为原料，合成了9种1,4-二氨基取代的蓝色蒽醌染料分子，探索了不同取代基对染料分子光物理性质、溶解性以及光热稳定性的影响。结果表明，所有染料分子在590~600 nm和630~650 nm波长范围内呈现双吸收峰性质，具有高的摩尔消光系数。其中三甘醇及单甲醚取代的染料分子热分解温度为300℃，在230℃加热0.5 h后失重约2%，365 nm波长光照射8 h后色差低于1.73，表现出优异的光热稳定性。研究为进一步制备光热稳定性优异的彩色光刻胶用染料分子奠定了基础。     

Comparison of disperse dye exhaustion,color yield,and colorfastness between polylactide and poly(ethylene terephthalate)

Ten popular disperse dyes with different energy levels and chemical constitutions were used to compare their exhaustion, color yield, and colorfastness on polylactide (PLA) and poly(ethylene terephthalate) (PET). Only two out of the 10 dyes had exhaustions higher than 80% on PLA at 2% owf. Five out of the 10 dyes had exhaustions less than 50%. All 10 dyes had more than 90% exhaustion on PET, whereas six of them had exhaustions of 98% or higher. There was no obvious pattern as for which energy level or which structure class provided dye exhaustion better than that of others. Although PLA had lower disperse dye exhaustion than that of PET, it had higher color yield. Based on the 10 dyes examined, the color yield of PLA was about 30% higher than that of PET. This means that even with low dye uptake, PLA could have a similar apparent shade depth as that of PET if the same dyeing conditions are applied. Our study supported that the lower reflectance, or reflectivity, of PLA contributes to the higher color yield of PLA than that of PET. A quantitative relation between the shade depth of PLA and PET based on their dye sorption was developed. Disperse dyes examined had lower washing and crocking fastness on PLA than on PET. The differences in class were about 0.5 to 1.0. If the comparison was based on the same dye uptake, the differences might be larger. The differences in light fastness between the two fibers were smaller than that in washing and crocking fastnesses. The light fastness of disperse dyes on PLA is expected to be even better if the comparison is based on the same dye uptake on both fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3285–3290, 2003     

Colour of flax fibres in regard to different pretreatment and dyeing processes

The main objective of this work was to compare the colour of different pretreated (alkaline, acidic and enzymatic) and dyed (conventional and ultrasonic-assisted) flax fibres, to establish the impact of various parameters on dyeing kinetics. Flax fibres were dyed using two direct dyes of different chemical structures and molecular mass. Diffusion profiles were established by the application of Fick's Law and dyeing behaviour was studied by means of online spectrophotometry. Finally, the dyed samples were colorimetrically evaluated and colour differences and colour strengths were subsequently calculated. The results provided evidence that a dye molecule's size has a greater influence on the exhaustion degree, migration and diffusion than individual pretreatment processes. The determined diffusion coefficients indicated superior dye mobility and faster diffusion into the fibres when ultrasonic power was used in comparison with conventional process. Nevertheless, the colour depth obtained was found to be low after ultrasonic dyeing using a larger dye molecule, implying part degradation of CI Direct Red 80 (and total degradation of small-size dyestuff, CI Direct Red 81).     

Digital printing of acrylic fabric with cationic dyes using conventional inkjet printer

A special printing ink formulation based on cationic dyes is developed for digital printing of acrylic fabrics using a conventional inkjet printer. In order to investigate the contribution of color gamut boundary of printer colorants to printing efficiency, customized color targets containing 3164 color patches in 25 different hues were generated. The printed color patches were then fixed through steaming for 30 minutes followed by washing with hot soap and water and finally drying. To show the influence of dye fixation on colorimetric changes as well as color gamut boundary of samples, the L*a*b* values of color patches before and after fixation process were compared. Results demonstrate that color saturation of samples is enhanced dramatically after the dye fixation process. In fact, 3D color gamut of color patches has been drastically expanded as a direct consequence of adsorption to absorption transition. Additionally, dye fixation changes the structure of printed image from halftone superimposed dots to contone superimposed dyes. Strictly speaking, during fixation process, colors inside the halftone dots diffuse through the interfacial area to make the individual printed dots integrated. This is in analogy to the chromogenic photography films and dye‐sublimation thermal transfer processes by which contone images are produced. Moreover, dye fixation improves the washing fastness of digitally printed acrylic fabrics to the level comparable with the traditional screen printing method. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 244–249, 2017     

The accessibility of cotton to anionic dyes

Adsorption isotherms have been obtained for two direct dyes on unmercerised cotton and viscose yarns at the boil in the presence of sodium chloride. Both dyes, CI Direct Red 81 and CI Direct Green 26, show evidence of monomolecular layer adsorption. Controlled acid hydrolysis of cotton was carried out in order to remove non-crystalline cellulose, and dye sorption values were obtained for the residues. Accessible surface areas have been calculated from the saturation values obtained from the reciprocal plots of the adsorption data. The results are interpreted in terms of a crystalline fibril model of the cotton fibre.     

基于粒子滤波的高浓度染料色泽软测量模型辨识方法

为了解决高浓度混合染料间歇染色过程织物色泽的在线测量问题,即非线性色泽软测量,提出了基于粒子滤波的软测量方法,该方法通过测定间歇染机内染液的吸光度,采用粒子滤波算法来估计该染液中各染料浓度,再根据染料浓度与织物色泽的软测量模型计算出染机内织物色泽。以3种活性染料拼染纯棉为例,对该方法的可行性进行验证。实例证明,基于粒子滤波的软测量方法的色泽估计值与人工离线实测值之间的色差值在1.0 CIELAB之内,模型的估计值能够满足工艺要求。因此,该方法是有效可行的。     

Effects of plasma treatment and metal-ion chelation on lightfastness of dyed polyester/cotton fabric

Polyester/cotton blend fabric was dyed with Chemistron dye—a mixture of reactive/disperse dyes. Dyed fabrics were subjected to radiofrequency (RF) plasma treatment of different duration and were subsequently treated with metal salts. The effect of surface modification by plasma and dye–metal complex on colorfastness to light is discussed. Evaluation of the improvement in lightfastness was made using the CIE system of color measurement with a standard illuminant D65 and 10° standard observer. The color parameters and color deviations were obtained by Data flash–100 color measurement spectrophotometer with chroma QC 3.0 color quality control software. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 292–299, 2001     

涤纶织物用分散染料的染色相容性的探讨

通过对五支分散染料的上染速率曲线、提升力曲线及色光变化分析,结合双拼色实验结果分析,结果表明,分散红3B、分散黄5GL和分散蓝2BLN组合在一起竭染时相容好。     

Impact of Ozonation on Decolorization and Mineralization of Azo Dyes: Biodegradability Enhancement,By-Products Formation,Required Energy and Cost

In the present study ozonation process was implemented to analyze the effect of ozonation time on the rate of chemical oxygen demand (COD) removal, mineralization and rate of decolorization of azo dyes. Three types of azo dyes i.e. Acid Red 14, Direct Red 28 and Reactive Black 5 were selected. Decolorization and mineralization of samples were conducted in batch scale. The COD and color removal efficiency were found to be increasing at a certain time of ozonation. The results with Acid Red 14, Congo Red and Reactive Black 5 dyes solutions lead to maximum COD reduction of 75%, 67% & 50% respectively. 93%, 92% and 94% color removal were achieved after 25 min of ozonation time of the same dyes which highlighted that ozonation process was found to be more efficient for reactive dye decolorization. Ozonation by-products analyzed by ion chromatography resulted that it partially mineralized with the formation of chloride, fluoride, sulphate, nitrate and oxalate ions. During ozonation process a rapid decrease in pH value indicated the acidic nature of by-products. The effect of buffered dye solutions on the ozonoation process highlighted that the decolorization efficiency decreases in comparison to unbuffered dye solutions. Ozonation led to enhancement of biodegradability ratio (BOD₅/COD) and increased electrical conductivity of the dye solutions. Optimum ozonation time required for degradation of dye solutions reflected the evaluation of energy consumption and cost of the treatment after ozonation.     

Influence of acid dyes on the thermal behavior of nylon 66

To reveal the effect of acid dyes on the melt processing of recycled nylon 66, 17 acid dyes with different chemical structures were used to dye a nylon 66 yarn. The thermal stability of dyestuffs, the thermal degradation of the dyed nylon 66 during compression molding, and the melting and crystallization of the dyed nylon were investigated. During melt processing, most dyed nylon 66 changed color strength and color pattern. This is attributed to the migration and chemical reactions of dyestuffs. Acid dyes containing metal ions, such as C.I. Acid Black 60, C.I. Acid Red 186, C.I. Acid Yellow 151, and C.I. Acid Black 107, have severe impact on the thermal stability of nylon 66. The influence of metal complex acid dyes on the thermal stability of nylon 66 can be explained by a mechanism of acid-catalyzed nucleophilic acyl substitution. It was observed that the existence of acid dye in nylon 66 does not influence the melting temperature of nylon. However, some metal complex dyes reduce the crystallization temperature of molten nylon. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 371–382, 1998     

The sensitivity and impact of dye structure and fibre micronaire on the increased dyeability of bioengineered cotton fibres

Previous research reported on a screening method to assess the functionalisation of bioengineered cotton fibres through the absorption of CI Acid Orange 7. The aim of the present paper is to extend this study to different dye classes. Thus the dye absorption of bioengineered cotton fibres containing oligochitin is studied for a series of dye classes. Statistically significant differences were found between cotton lines designed to produce oligochitin in the fibre and their respective controls for all tested dyes, confirming previous results with CI Acid Orange 7. Further, although variations in micronaire influenced dye absorption, it was confirmed for all dyes tested as well as for CI Acid Orange 7 that the oligochitin production had a larger impact on the exhaustion values than the differences in micronaire. The method described in this paper can be applied as a screening tool to meet the challenge of working with small quantities of fibrous materials. Moreover it shows the potential that the incorporated oligochitin has for increasing dyeability with a wide range of dyes and creating fibres with more versatile reactivity.     

Methods and impact of reducing salt in dyeing cellulose: a case study with CI Direct Blue 90

The addition of large amounts of salt is one of the most important environmental problems in the dyeing of cellulosic fibres with direct or reactive dyes. This study was undertaken to determine an accurate and effective method for measuring the impact of salt on the dyeing process. This method has been applied to the case of CI Direct Blue 90 by utilising real‐time measurements of dye exhaustion for different salt and dye concentrations. Reductions in salt by a factor of 4 were achieved with no effect on the final shade. It is proposed that this method could be used to reduce the amount of salt for many other direct dyes, or to enable the dyer to quantify the trade‐off between time to final exhaustion and salt addition.     

热敏打印技术及热敏染料在彩色影像输出中的应用

全彩色热敏打印由于具有影像质量高、使用方便、利于环保等优点,成为彩色影像输出技术领域的发展方向。荧烷化合物具有在熔点下从无色到有色的互变结构,可通过变换取代基,得到黄、品、青系列染料,成为应用在热敏彩色影像输出技术中的主要染料类型。     

New insights into dye chemistry and physics

A review of the academic dye research performed by the Port Sunlight group and its coworkers over the past 15 years is presented. The work is focused on three areas: (1) substrate structure; (2) dye interactions in aqueous solution and on substrates; (3) dye degradation and products. For substrates, a detailed model of the nanoenvironment experienced by chemicals within cellulose fibre is given, showing the different environments and remarkable mobility of absorbed chemicals. Advanced nuclear magnetic resonance diffusion measurements provide the complex pathways by which compounds find their way in and out of the fibre. For dye interaction, detailed theoretical and experimental studies are reported on three model dye systems, the anionic monoazo dye Orange II, the bisazo anionic dye CI Direct Blue 1, and cationic monoazo thiazolium dyes, providing a comprehensive picture of their structure. A quantitative mechanism of dye binding to cellulose is shown. Resonance Raman provides an effective forensic tool for dye identification, even from single fibres. The products and kinetics of Orange II dye degradation by one‐electron reduction in aqueous solution is given, with the identification of an indophenol dye end‐product. In cellulosic materials the reduction mechanism is similar to solution, when the higher microviscosity is accounted for. Hydrolysis of thiazolium dyes occurs at both aromatic rings of the dye but on different timescales. Measurement and calculations of the electronic structures of one‐electron‐reduced and ‐oxidised dyes are presented. The mechanism of photooxidation by sunlight of azo dyes in cotton is delineated.