A study of reusing vinyl sulfone based reactive dye for dyeing cotton fiber

Reactive dye is a popular dye for dyeing cotton fiber due to its very good color fastness which is explained by the formation of covalent bond between dye and fiber. In this study, practicality of reuse of reactive dye by compensating for the hydrolyzed part of the dye solution is examined. A monofunctional dye (vinyl sulfone type) was used and it was found that dyeing cotton fiber with reused dyebath is possible. Since bifunctional dye can improve the chance of dye-fiber bond formation, vinyl sulfone based bifunctional reactive dyes were also selected in this study. Three types of bifunctional dyes were used and they basically share the same vinyl sulfone group; other reactive groups are monochlorotriazine, dichlorotriazine and vinyl sulfone. Such dyes were chosen in order to compare their respective efficiencies under the effect of one common reactive group. The aim of this study was to compare the effect of hydrolyzed and unhydrolyzed proportions of mono-and bifunctional reactive dyes on cotton fiber and study the possibility and efficiency of the two different reuse dyebath systems.     

UV protective properties of cotton fabric treated with plasma,UV absorber,and reactive dye

The influence of water vapor plasma on the adsorption of UV absorber during the reactive dyeing of bleached and mercerized cotton fabric was examined. Exhaust dyeing of untreated and plasma-treated cotton was performed using a reactive dye Cibarcon Deep Red S-B and a commercial UV absorber Tinofast CEL. Blank dyeing was performed as a control experiment. Fourier transform infrared spectroscopy (FTIR) was used to identify the presence of the UV absorber on the cotton fabric, whereas scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze surface changes of untreated and plasma-treated dyed samples. The CIELAB color values and ultraviolet protection factor (UPF) of the samples were determined spectrophotometrically. Wash and light fastness of samples was performed also. The results reveal that the UPF of cotton increases after UV absorber treatment and that plasma treatment increases the adsorption of UV absorber during dyeing process, especially at higher dye concentrations. The enhanced adsorption of UV absorber onto plasma-treated cotton is the result of the increased concentration of oxygen containing functional groups on the cotton surface after plasma treatment, confirmed by XPS. The UPF of plasma-treated cotton samples is decreased after washing and increased after exposure to xenon light.     

A novel approach for estimating the relation betweenK/S value and dye uptake in reactive dyeing of cotton fabrics

This paper focuses on the application of a novel mathematical limit approach derived forK/S values in reactive dyeing of cotton fabrics. The relation obtained from Kubelka-Munk equation is used because the Kubelka-Munk equation is the basic relationship among fabric reflectance, fabric dye content and dyestuff characteristics. The limit approach derived in a former paper is applied to the laboratory dyeings and the dyeing behavior of some reactive dyes on cotton knitted fabric has been obtained. The results of the laboratory experiments are discussed using the new mathematical approach. When the actualK/S values obtained from the dyeings and the calculatedK/S values derived by the limit approach are considered independently, it is observed that the limit relation is valid for low dye concentration applications. When theK/S values are calculated taking theK/S value of the initial dyeing concentration (0.1 % owf) as the starting concentration by applying the result of the derived limit approach, the calculatedK/S values fit with the ones obtained in actual dyeings. It is concluded that the novel approach presented in the paper can be used in calculating theK/S values when the initial dyeings at low dye concentrations are carefully carried out.     

Dyeing properties and colour fastness of wool dyed with indicaxanthin natural dye

This research work involves the dyeing of wool with indicaxanthin, a natural dye extracted from fruits of Opuntia ficus-indica. The optimal conditions for dye extraction were to mix 50 g of Juice from cactus pears with 100 mL of 80% aqueous ethanol as solvent for dye extraction. Liquid chromatography was applied for the separation. Two main dyes were obtained, which were identified as indicaxanthin (75 mg per 50 g) and betanin (5 mg per 50 g). The effect of dye bath pH, salt concentration, dyeing time and temperature were studied. The optimal conditions for wool dyeing with indicaxanthin dye were carried out at 70 °C for 90 min with the pre-treatment of various metal salts as mordant. The colour yields of the dye on the wool were found to be highly dependent of the pH, optimum results being obtained at pH 4. The K/S of wool increased in the order of the dyeing using KAl (SO₄)₂ > MnSO₄ > CoSO₄ > FeSO₄ > none > ZnSO₄ > CuSO₄. Un-mordanted samples have good properties of water and washing fastness. Mordants KAl (SO₄)₂ and CoSO₄ were found to give good light fastness (rating 5).     

Intergenerational differences of color sensation and preference for naturally dyed fabrics

This study was performed in order to evaluate subjective color sensation and preference for yellowish and reddish natural dye fabrics and to provide meaningful objective colorimetric properties which can quantify the sensation and preference focused on intergenerational differences. Among lots of natural dye silk fabrics, four differently dyed fabrics for each hue were used as specimens by cluster analysis. College students as younger generation and high school teachers as middle-aged evaluated them subjectively in terms of eight aspects color sensation such as clearness, lightness, depth, warmth, strength, brightness, hardness, and fragrance. Intergenerational differences appeared more frequently as for the lightest and the most saturated yellowish fabrics dyed with amur cork than any other fabrics. All of sensation and preference were significantly explained by some colorimetric properties for each generation. Color lightness, L* was the only positive predictor for color preference of younger generation’s preference whereas color saturation, C* illustrated negatively for that of middle-aged.     

Computerized color separation system for printed fabrics by using backward-propagation neural network

Textile production must be coupled with hi-tech assistant system to save cost of labor, material, time. Therefore color quality control is one very important step in any textiles, however excellent the fabric material itself is, if it lacks good color, then it may still result in dull sale. Therefore, this paper proposes a printed fabrics computerized color separation system based on backward-propagation neural network, whose primary function is to separate rich color of printed fabrics pattern so as to reduce time-consuming manual color separation color matching of current players. What it adopted was RGB color space, expressed in red, green, and blue. Analyze color features of printed fabrics, use gene algorithm to find sub-image with same color distribution as original image of printed fabrics yet smaller area, for later color separation algorithm use. In terms of color separation algorithm, this paper relied on supervised backward-propagation neural network to conduct color separation of printed fabrics RGB sub-image, and utilized PANTONE® standard color ticket to do color matching, so as to realize accurate color separation.     

Antibacterial properties and color fastness of silk fabric dyed with turmeric extract

The use of non-toxic and eco-friendly natural dyes on textiles has received much attention due to the increased environmental awareness in order to avoid some hazardous synthetic dyes. In the present study, an eco-friendly approach was developed to impart color and antibacterial properties to silk fabrics dyed with turmeric extract as a non-toxic natural colorant. The natural colorant was extracted from Curcuma Longa rhizome. Copper sulfate, ferrous sulfate and potassium aluminium sulfate were applied in a pre-metallization process as mordanting agents. Antibacterial properties of treated fabrics were evaluated against common pathogenic bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The effects of dye concentration and mordant types on the obtained color hues, antibacterial efficiency and color fastness of the fabrics were investigated. The results indicated that mordanted and dyed fabrics possessed desirable antibacterial properties. Complete antibacterial activity of the treated fabrics was obtained with 3 %owf (on weight of the fabric) copper sulfate. It was also shown that increasing the dye concentration could lead to a more efficient antibacterial activity on the mordanted dyed fabrics. An optimum level of the antibacterial activity was observed in the sample treated with 30 %owf of turmeric. Furthermore, the results of CIE L*, a*, b* values, FTIR, washing, light and rubbing fastnesses of the dyed fabrics were reported. The mordanted dyed silk fabrics exhibited desirable color fastness properties. These studies proved a direct relationship between the degree of antibacterial activity of the fabrics treated with turmeric and the metals ion concentration.     

The use of k-means and artificial neural network to classify cotton lint

The use of High Volume Instrument (HVI) to measure cotton lint characteristics produces high dimensional data. A model which utilized Kohonen Self Organizing Maps (SOM) to visualize cotton lint HVI data, k-means clustering technique to cluster the data and Probabilistic Neural Network (PNN) for data classification was designed and tested using Kenyan cotton lint. According to the model the Kenyan cotton lint can be grouped into four clusters, which were successfully classified by using PNN with a correlation coefficient (R-value) of 1.     

Estimating regional productivity based on demographic structure with artificial neural network

This paper explores the impact of the age structure on regional productivity. An estimation model based on artificial neural network (ANN) was developed on the assumption that demographic change, due to aging and migration has a significant effect on the regional productivity, especially in rural regions. A multilayer perceptron ANN model was applied to consider the composition of demographic structure rather than ratio between two population groups such as aged-child ratio. Regional productivity was estimated by applying the estimation model developed in this research study to population and aggregate product data of sixteen South Korean cities and counties, from 2000 to 2011. Developed model is trained with data of sixteen cities and counties, from 2000 to 2009, and verified with observation data and estimation results of 2010 and 2011. The results revealed that gross regional domestic product per capita, which represents regional productivity, is significantly related to demographic structure and can be estimated by age structure.     

Evaluation of scanner capability for measuring the color of fabrics with different textures in different setups

The influence of surface texture on the perceived color by a flatbed scanner is investigated. Knitted fabrics with 8 different textures in variety of colors are prepared and used in scanning trial along with standard chart, i.e. IT8.7/2 from Kodak. According to the results, the scanner detects different RGB values for different textures which are weaved from same colored yarns. The means of R, G and B values are considered as a feature vector which shows the dominant color of each sample. Samples are scanned with different resolutions and it is found that scanning resolution does not change the extracted color feature vector. The IT8.7/2 standard target which benefits from non textural solid surface and fabrics with specific surface texture are used for colorimetric characterization of scanner and the capability of scanner for estimation of color coordinates of samples with different textures is examined. It is found that the characterization of scanner with textured target improves the scanner accuracy for the color of textured materials. It is shown that the texture of media has a great effect on the characterization results and there is relatively good correlation between the structural differences of textures of fabrics used in training and testing steps with the mean of testing color difference values. To achieve a better color reproduction results for fabrics, scanner characterization should be performed for each set of fabrics with specific texture. In this case, increasing the bit depth of captured image in the scanning process leads to decrease of the mean of color difference value for training and testing packages.     

Using artificial neural network to predict colour properties of laser-treated 100% cotton fabric

In this paper, artificial neural network (ANN) model was used for predicting colour properties of 100 % cotton fabrics, including colour yield (in terms of K/S value) and CIE L, a, and b values, under the influence of laser engraving process with various combination of laser processing parameters. Variables examined in the ANN model included fibre composition, fabric density (warp and weft direction), mass of fabric, fabric thickness and linear density of yarn (warp and weft direction). The ANN model was compared with a linear regression model where the ANN model produced superior results in prediction of colour properties of laser engraved 100 % cotton fabrics. The relative importance of the examined factors influencing colour properties was also investigated. The analysis revealed that laser processing parameters played an important role in affecting the colour properties of the treated 100 % cotton fabrics.     

基于神经网络的甘蔗产量预测系统

首次将人工神经网络应用到甘蔗产量的预测中,介绍了ＢＰ网络模型及其算法,讨论了系统的开发方法,并对系统进行验证。对广西忻城糖厂蔗区８８／８９－９７／９８榨季的甘蔗单产和相应的气象条件运行结果表明模型具有较高的精度,复测误差在－５．３－１０．２％。     

A technique of cotton bale laydown using clustering algorithm

A new technique of cotton bale management using clustering algorithm has been proposed. The method is based on the grouping cotton bales of similar kind into respective categories using k-mean square clustering algorithm. A set of 500 cotton bales were clustered into 5 categories by minimizing the total within-group squared Euclidean distance around the 5 centroids. In order to cluster bales of different categories, 8 fibre properties, viz., strength, elongation, upper half mean length, length uniformity, short fibre content, micronaire, reflectance and yellowness of each bale have been considered. Once the bales are clustered into different categories, it is possible to prepare consistent bale mix for consecutive laydowns on the basis of frequency relative picking method.     

A psychophysical approach to color sensory evaluation of yellowish natural dye fabrics

The objectives of this study were to evaluate color sensation for yellowish natural dye fabrics using magnitude estimation to determine physical colorimetric factors significantly related to human sensibility by establishing power function in psychophysical analysis. Fourteen different yellowish fabrics dyed with natural colorants were selected as stimuli. Subjective color sensations including brightness, heaviness, softness, strength, warmth, activeness, classicalness, femininity, and pleasantness for each stimulus were subjectively evaluated by using fixed magnitude estimation. As results, yellowish natural dye fabrics in general seemed to evoke feeling of brightness, femininity, and pleasantness more strongly than that of heaviness and classicalness. Most of color sensations were significantly related with more than one of physical color properties, which leads to establishing reliable power functions between them. Color lightness, L* was found as a dominant physical attribute which affects subjective sensation such as brightness, femininity, and pleasantness. Subjective activeness was explained by physical yellowness, b*, whereas both strength and classicalness were by color saturation, C* even though it described strength positively while it did classicalness negatively. In the power functions, these relationships could be utilized to design color-sensible natural dye textiles.     

Deodorizing and antibacterial performance of cotton, silk and wool fabrics dyed with Punica granatum L. extracts

Natural dye extracts were obtained by extraction from Punica granatum L. using water as an extractant at 90 °C for 90 min with various liquor ratios (solid Punica granatum L.(wt.): solvent water(wt.); 1:100–1:5). Dyeing was carried out using a 1:50 dyeing bath ratio at 80 °C for 60 min by exhaustion method. This study focused on the effect of liquor ratio on dyeing properties and deodorizing/antibacterial performance of various fabrics (cotton, silk and wool) dyed with Punica granatum L. extract without mordants. The optimum liquor ratio was found to be 1:10. By IR, UV-visible spectroscopies and HPLC analysis, the main component in Punica granatum L. extract and the yellow colorant component were found to be ellagic acid. By GC/MS analysis, the major volatile components of pristine Punica granatum L. powder were found to be acetic acid (area: 25.84 %), ethanol (area: 17.97 %), acetoin (area: 13.11 %), acetaldehyde (area: 8.96 %), isobutanal (area: 4.90 %). All dyed fabrics (cotton, silk and wool fabrics) displayed outstanding deodorizing performance (99 %) against ammonia gas and excellent antibacterial performance (bacteriostatic reduction rate: 99.9 %) against Staphylococcu aureus and Klebsiella pneumoniae.     

Optimization of dyeing condition for wool/cotton union fabric with direct dye using box-behnken design

Wool/cotton union fabric was dyed with a direct dye in union shade. The dyeing was performed in a single bath in relation to four factors: leveling agent (Lyogen SMKI, 0–1.5 % oww), electrolyte (sodium sulfate, 0–10 %), dyeing temperature (85–95 °C), and dyeing time (15–60 min). The dyeing was characterized by dye bath exhaustion (%), color strength (K/S value), washing fastness, and light fastness of dyed sample. Response surface analysis showed that the exhaustion of direct dye increased with electrolyte, dyeing temperature, and dyeing time while the K/S value followed a linear shape with leveling agent and dyeing temperature. An optimized recipe was formulated based on response surface strategy and numerical optimization solution.     

An artificial neural network approach to prediction of the colorimetric values of the stripped cotton fabrics

This paper presents an artificial neural network (ANN) modeling by Levenberg-Marquardt (LM) algorithm for predicting the colorimetric values of the stripped cotton fabrics dyed using commercial reactive dyes. Achieving the expected efficiency in the application of stripping process is a very important aspect for the success of the reproduction. In the study, the predictions of L* and ΔE colorimetric values of stripped cotton samples for different stripping applications by artificial neural network are reported. We set up different network structures with different number of nodes in the hidden layer, the number of inputs and MSE of results as stopping criteria in order to get the best fitting model. According to the result of the best neural network models predicting L* and ΔE, we achieved 97 % of R for both of them. We are able to predict the L* value of the stripped samples using some working parameters as inputs with only 1.2 % error. We think that our results are very promising and the predictions of L* and ΔE values of stripped samples before applying any process are possible using the ANN model set up in the study, especially for L*.     

Ultrasonic dyeing of cationized cotton fabric with natural dye. Part 2: Cationization of cotton using Quat 188

The dyeing of cationized cotton fabric with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride 69% (Quat 188) using Cochineal dye was studied using both conventional and ultrasonic techniques. Factors affecting dye extraction and dye bath exhaustion were investigated. The results indicated that the dye extraction by ultrasound at 300 W was more effective at lower temperatures and times than conventional extraction. Also, the colour strength values obtained were found to be higher with ultrasound than with conventional techniques. However, the results showed that the fastness properties of the dyed fabrics with ultrasound are similar to those of the conventional dyed fabrics. The scanning electron microscope (SEM) and X-ray diffraction (XRD) were measured for cationized cotton fabrics dyed with both conventional and ultrasound techniques, thus showing the sonicator efficiency.     

Application of liquid organic salt to cotton dyeing process with reactive dyes

Reactive dyes are used widely in cotton dyeing process. Reactive dyeing uses high amounts of inorganic salts to accelerate dye exhaustion. These salts are then discharged to the effluent, leading to serious environmental problems. Biodegradable organic salts can alternatively be used in the dyeing process. In this paper, a new liquid organic salt was synthesized by acid-base neutralization, which was used to replace inorganic salts in reactive dyeing. Dye exhaustion in organic salt dyeing was similar to the values in conventional dyeing. However, dye fixations were slightly lower in organic salt dyeing than in conventional dyeing. The washing fastness of dyed fabrics with organic salt was excellent. Experimental results showed that dye exhaustion reached the maximum value when the concentration range of organic salt was from 20 g/l to 40 g/l. In addition, the optimal alkali concentration in organic salt dyeing was found to be about 30 g/l. These parameters suggested organic salt could replace inorganic salt in reactive dyeing process.