Relative Color Strength Research Articles

Going Green for Blue - An Indigo Approach

Introduction: Dominating use of chemical processes for reducing indigo at several small-scale production houses formed the ground for initiating this study. Conventional textile processing hubs still use sodium hydrosulphite as a reducing agent irrespective of the source of indigo, whether natural or synthetic ignoring the unfavourable consequences of their disposal and elimination from effluent Method: The paper addresses the critical environmental issues related to the conventional reduction of indigo and studies already undertaken. It examines the indigo dyeing process of cotton using natural, chemical and eco-friendly reducing agents in combination with calcium hydroxide for a comparative study. Identification of natural indigo through High-Performance Liquid Chromatography was undertaken for further experimentation. Under specific parameters, the study examined the effect of Thiourea dioxide and natural reducing agents in indigo dyeing replacing Sodium hydrosulphite. The difference in weight, strength, and colour parameters such as K/S (HUNTERLAB), CIELab values and colourfastness are measured. The experimental results showed weight gain in all fabrics after indigo dyeing. There is a decrease in weft strength only in tamarind, iron, jaggery and dextrose vats. Iron vat showed a higher colour yield out of all reducing agents due to forming metal complexes with the cotton fabric, which influenced colour depth and highest relative colour strength % (114.11) and ΔC (8.48). Result: Thiourea dioxide showed the next highest relative colour strength % (96.59) and lowest ΔH values (8.54) concerning the values of the hydro process. Structural changes of fiber were studied by using SEM (Scanning Electron Microscope) after using different reducing agents, which revealed superior surface topography of samples dyed using thiox. The colour difference showed no significant effect on the colourfastness of alternative reducing agents. Conclusion: Thiox can be a perfect substitution for hydro in indigo dyeing as it was found practical and feasible for implementation even by small-scale units in India.

A new method for determination of the relative colour strength of dye based on new colour depth formula. Part II: application to different batches of colourant

AbstractAs a standard for the evaluation of relative colour strength (RCS) of dye, AATCC EP‐6 (SWL [K/S], SUM, and WSUM) has been widely used, while its limitations are often overlooked by people. In Part I of this study, the new method Yangn (CSV1, CSV2, and CSV3) for the determination of RCS were proposed, Yangn and AATCC EP‐6 were tested using the different types of disperse dyes that have approximate hues. However, the calculations of RCS for the same dyes produced in different batches were also necessary, therefore, this article (Part II) focuses on it. The HL series dyes produced in 2020 and 2021 were used to test Yangn and AATCC EP‐6. The same results as Part I, the colour strength values calculated by SWL, SUM, and WSUM were inconsistent. Furthermore, in the methods of AATCC EP‐6, the colour strength values calculated by WSUM should be at least rounded to four decimal places to avoid false calculation; the value of Yangn only need to be rounded to two decimal places. For the RCS of the same dyes produced in different batches, the methods of AATCC EP‐6 and Yangn were relatively the same under different dyeing concentrations. The coefficient of variation (CV) values of Yangn were < 1.3%, the CV values of AATCC EP‐6 were < 2%. Therefore, according to the consistency of the calculation, the CV values and the dependence on the concentration, the new methods of Yangn were superior to the traditional methods.

A new method for determining relative colour strength of dye based on new colour depth formulas. Part I: For different dyes with approximate hue

AbstractRelative colour strength (RCS) of dye plays an important role in the production, the evaluation and the application of dyes. There are different standards on the determination of it, their principles are all related to colour depth. However, the standard methods have some limitations. For this purpose, this study proposed a new method for the RCS based on the new colour depth formula Yangn, which included three methods named colour strength value (CSV1, CSV2 and CSV3). Part I in this study was to investigate the application effect of Yangn on the RCS of different disperse dyes with approximate hues. According to the experimental results of E‐type and SE‐type disperse dyes, the new method showed its advantages. Firstly, compared with AATCC EP‐6, the results of the new method were more consistent. Secondly, under different dyeing concentrations, the RCS values of the new method were relatively consistent, with average coefficient values (CVs) being less than 5%, especially for CSV3 with only 3.59%; while all the average CVs of AATCC EP‐6 were greater than 6%. For the calculation of RCS of different types of dyes with approximate hue, the new method presented more accurate results.

Dyeing silk and cotton fabrics using Fuji apple peel and the properties of the dyed fabrics

A new source of natural dyes, which possessed antibacterial and UV protection properties, was proposed. Natural dyes were extracted from Fuji apple peel. The extract contained two anthocyanins and five quercetin glycosides. Silk and cotton fabrics were dyed using the extract with and without six types of mordants: Mg2+, Ca2+, Al3+, Ti4+, Fe3+, and Cu2+. The properties of the dyed fabrics were investigated by various means. The K/S values were used to show relative color strength of the dyed fabrics and the CIELAB color system was used to show the color hue of the dyed fabrics. The crystallinity of the silk was lower than that of the cotton. The silk was dyed deeper than the cotton regardless of the dyeing conditions, including dyeing temperature, dyeing period, and solution pH. This result comes from the existence of carboxyl and amino groups and low crystallinity of silk fibers. Fabrics with various colors, including pink, green, brown, and gray, were obtained by mordant dyeing. The dyed fabrics had splendid performance; that is, antibacterial and UV shielding properties. Color fastness to washing (color change) was comparably low but was enhanced with Ti4+ and Fe3+ mordants.

Dyeing of cotton fabric with Euclea divinorum extract using response surface optimization method

PurposeThe majority of the synthetic dyes have been found to be non-biodegradable, toxic and carcinogenic. As a result, there has been a growing trend toward the use of natural dyes as alternates to synthetic dyes. This shift calls for more research to come up with more sources of natural dyes to satisfy their increasing demand. Euclea divinorum plant has been used traditionally as a source of dye, however, its textile dyeing properties have not been studied. This study aims to determine the textile dyeing properties of E. divinorum extract.Design/methodology/approachOptimization of dyeing conditions of Euclea divinorum natural dye extract on the cotton fabric was done using response surface methodology (RSM). The combined effects of examined dyeing conditions on the relative color strength (K/S) were studied using a central composite experimental design. Analysis of variance (ANOVA) was used to determine the significance of the statistical model generated for the study. Mordanting effects were measured using standard ISO wash, rub and lightfastness tests.FindingsThe optimum dyeing conditions were found to be 68 min, pH 3.3 and 82°C with color strength 0.609. Temperature and pH showed some interaction effects during the dyeing experiments. The predicted optimum K/S value was validated experimentally using the optimum conditions and was found to be in agreement with the experimental values. All the metallic mordants used enhanced the color strength and provided a variety of brown shades, therefore, a suitable alternative for the toxic synthetic dyes.Originality/valueOptimization of dyeing conditions of Euclea divinorum dye on cotton using RSM and mordanting at optimal conditions has not been done elsewhere.

Sustainable dyeing of selected natural and synthetic fabrics using waste teak leaves (Tectona Grandis L.)

PurposeThis paper aims to extract the dye colourant from teak leaves using different aqueous mediums (Alkaline, Neutral and Acidic); to characterize the dye in terms of yield %; ash content and moisture content; to standardize the conditions of application of dye extracted from teak leaves on selected natural and synthetic fabrics using selected natural and chemical mordants; to assess the colour value (K/S, L*, c*/ h*, a*, b*) and fastness properties of the dyed samples in terms of wash, rub, light and perspiration fastness; and to develop dyed and printed designs using combinations of mordant and extracted dye.Design/methodology/approachStage 1 – Extraction of dye from teak leaves; and characterization of dye: yield% ash content and moisture content. Stage 2 – Preparation of fabrics for dyeing; optimization of mordanting parameters using pre mordanting method followed by post mordanting; and optimization of dyeing parameters. Stage 3 – Testing of dyed fabric – Colour Measurement; K/S L*a*b*/L*c*h*; fastness properties; wash fastness done in the Laundrometer using ISO 2 standard test method; crock fastness done by Crockmeter using AATCC 116–1995 test method; perspiration fastness tested by perspirometer using AATCC 15– 2007 test method; and light fastness assessment in Mercury Bulb Tungsten Filament (MBTF) light fastness tester using AATCC Test Method 16–2004.FindingsThe findings of the study show that waste teak leaves can be used as an effective dye for natural as well as synthetic fabrics giving a wide range of colours on wool, silk and nylon. The maximum relative colour strength of the extracted dye on unmordanted dyed samples was found to be at pH 5 on wool and silk and at pH 7 on nylon. A range of shades was obtained with the use of different mordants. The extracted dye showed moderate to good fastness properties in terms of light, wash, rub and perspiration on wool and silk and excellent on nylon. Fastness properties were found to improve with the application of mordants both as pre and post method. Various combinations of mordants and dye result in obtaining pleasing and harmonious colours which were used aesthetically for printing.Research limitations/implicationsDue to time constrains, extraction in an organic medium could not be done, which could be a further scope for study.Practical implicationsDyeing using teak leaves is a step towards sustainability and effective waste utilization with promising potential for application on natural as well as synthetic fabrics. Good colour with added properties will provide excellent solutions for eco-friendly methods of dyeing.Social implicationsThis paper demonstrates the new possibilities offered by innovative uses of by-products of the timber industry and open good prospects for alternatives to synthetic colourants and new markets for the textile industry. It offers a new tool for the development of slow fashion.Originality/valueIt is a common practice to prune the tree branches to improve wood quality; thus, leaves are easily available as by product from pruning and also from wood harvesting. In the present study, waste teak leaves (Tectona grandis L.) were used for the extraction of dye.

Assessment of the Use of Natural Extracted Dyes and Pancreatin Enzyme for Dyeing of Four Natural Textiles: HPLC Analysis of Phytochemicals

In the present study, four natural textiles (cotton, linen, wool, and silk) were dyed with 14 naturally extracted dyes, and pancreatin enzyme was used in the dyeing process. The effects of pancreatin enzyme and its buffer on naturally dyed textile samples were evaluated. Two concentrations of pancreatin enzyme and buffer were used as pretreatments for dyed textiles. Proteinic fabrics showed the highest relative color strength (RCS) values of 137.23% and 132.2% when the pancreatin enzyme was applied on wool and silk dyed with pomegranate skin and bloodroot at concentrations A and B, respectively. Linen fiber dyed with catechu tree showed the highest total color difference (TCD) values with buffer (6.83) and pancreatin enzyme A (5.7) and B (6.3). This shows that there were no side effects of the pancreatin enzyme on the studied dyed textiles. By high-performance liquid chromatography (HPLC) analysis, the root extract from madder showed the presence of salicylic acid (1758.91 mg/kg extract), quercetin (844.23 mg/kg extract), ellagic acid (784.86 mg/kg extract) and benzoic acid (582.68 mg/kg extract) as main compounds. In cochineal extract the main compounds were rutin (37.732 mg/kg extract), kampherol (1915.98 mg/kg extract), myricetin (809.97 mg/kg extract), quercetin (496.76 mg/kg extract) and salicylic acid (193.87 mg/kg extract).

Effects of the extrusion processes on the rheological, chemical, and coloration properties of a copper phthalocyanine-based masterbatch

The production process of a monodispersed blue masterbatch for the coloration of the carpet filaments, constituted by a polyamide 6 (PA6) resin and a copper blue phthalocyanine pigment, was investigated and optimized. It was found that a compounding process based on three extrusions without any subsequent filtration was the best way to achieve a fine pigment dispersion within the PA6 matrix, with a filter pressure value reduction of 50% and a relative color strength increase of about 10% with respect to the standard production process (i.e. a single extrusion). Rheological tests, viscosity measurements and end groups analyses were used to determine the thermal stability of the prepared compounds. It was found that the triple extrusion promoted thermo-oxidative reactions. This innovative process setup can reduce the production waste, increasing the productivity and the quality of the final product without compromising the rheological properties of the monodispersed masterbatches.

Antibacterial Efficiency of Mordant-Treated Cotton and Polyamide Fabrics, Before and After Dyeing

ABSTRACTDyeability of cotton and polyamide fabrics which were treated with some mordant (such as silver nitrate, copper chloride, and nickel nitrate) and antibacterial activity of them before and after dyeing were studied. The fabric samples were inoculated in mordant solution, then were dyed using acidic, basic and direct dyes. Color intensities of dyed fabrics were measured by using a UV VIS-NIR reflective spectrophotometer, over the range of 350–750 nm. The results show that, by using different mordant before dyeing, the relative color strength (K/S values) of dyed fabrics increase. This effect is more significant in case of using basic dyestuffs.Antibacterial efficiency of treated fabrics was tested against gram-positive bacteria Staphylococcus aureus. Treated cotton and polyamide fabrics show excellent antibacterial efficiency. The morphology of fibers treated with metallic salts before and after dyeing was assessed by SEM (Scanning Electron Microscopy). The main aim of this study was to examine the influence of dyeing on antibacterial efficiency of metallic salts–treated cotton and polyamide fabrics.

Influence of the Processing Parameters on the Dispersion and Coloration Behavior of a Halogenated Copper Phthalocyanine‐Based Masterbatch

AbstractA monodispersed green masterbatch was produced through an industrial extrusion process, by mixing a commercial Polyamide 6 matrix (PA6) with a halogenated copper phthalocyanine green pigment. The production process was investigated and optimized in order to improve the pigment dispersion, reducing the clogging power and increasing the color strength of the resulting products. The compounding process based on three extrusions without filtration led to a filter pressure value (FPV) reduction of about 84% and a relative color strength (RCS) increase of about 50% with respect to the standard production process (i.e single extrusion). The thermal stability of the prepared compounds was evaluated by rheological test, viscosity measurements, and end group analysis, and it was found that a triple extrusion without filtration promoted thermo‐oxidative matrix degradation. However, the same processing conditions led to a significant reduction of the production waste, increasing the productivity and the quality of the final product.

Extraction of eco-friendly natural dyes from mango leaves and their application on silk fabric

The aim of the study was to evaluate the performance of dyes extracted from mango leaves in silk dyeing. Extraction medium was optimized by extracting dyes from fixed quantity of crushed leaves under pH values from 3 to 12. The maximum relative color strength of the extracted dye liquor was found to be at pH 10. The optimum dye extraction conditions i.e., the temperature, time, and material-to-liquor ratio were found to be 98 °C, 60 min, and 1:10, respectively. Dyeing was carried out with the optimized dye extract on mordanted and unmordanted silk fabrics. The dyed materials were evaluated by measuring the color yield and fastness properties. It was concluded that the color values were found to be influenced by the addition of mordants, consequently different fashion hues were obtained from the same dye extract using different mordants. It can also be said that mango leaves have good potentiality for dyeing of silk fabric.

Dyeing properties of the atmospheric pressure plasma-treated polypropylene fabric subjected to butane tetra carboxylic acid

In this paper, dyeing properties of dielectric barrier discharge (DBD)-treated polypropylene (PP) fabrics padded with butanetetracarboxylic acid (BTCA) were evaluated. We have used a DBD, working in an atmospheric pressure air. More polar functional groups were presented on the substrate surface after DBD pretreatment. After DBD treatment, BTCA was applied to PP fabrics by pad–dry–cure system. Both treated and untreated fabrics were dyed using acidic and basic dyestuffs. The surface morphology was investigated by scanning electron microscopy images. Treated samples were also characterized by means of Fourier transform infrared spectroscopy. The wettability of the samples was evaluated by water drop test according to AATCC 79-2000 standard. Color intensities of the dyed fabrics with both acidic and basic dyestuffs were measured using a UV–vis–NIR reflective spectrophotometer, over the range of 400–700 nm. The results showed that, by treating the fabric, the relative color strength (K/S values) of the dyed fabrics has been increased. From the results of tensile strength test, both weft and warp directions, no significant difference was obtained within the accuracies of the measurement. Also, the fastnesses properties of samples were measured.

Eco-friendly dyeing of wool and pashmina fabric using Quercus robur L. (fruit cups) dye and Salix alba L. (wood extract) mordant

Study was conducted to investigate the dyeing potential of Quercus robur L. (fruit cups) dye and Salix alba L. (wood extract) mordant on wool and pashmina fabrics. The experiment was conducted keeping in view the environmental safety by using unutilized plant materials and excluding the usage of chemical agents. The dyeing was carried out individually including and excluding mordant adopting different mordanting methods. The parameters like percent absorption, colour coordinates, colour strength (K/S), relative colour strength and colour fastness with regard to washing, light and rubbing were investigated. The results revealed higher percent absorption of mordanted samples than unmordanted samples. Colour coordinates (L*a*b*, Chroma, hue and ?E) of dyed wool and pashmina fabric exhibited satisfactory results. The colour strength (K/S) and relative colour strength of pashmina fabric recorded higher than wool fabric. The fastness properties to washing, light and rubbing showed satisfactory grades including and excluding natural mordant. However, the grades of mordanted samples were found better than unmordanted samples. The dye and mordant in isolation and in combination showed beautiful colours and shades on selected fabrics with satisfactory retention properties, hence can be utilized commercially for coloration of wool and pashmina fabrics.

Mixture approach for optimizing the recovery of colored phenolics from red pepper (Capsicum annum L.) by-products as potential source of natural dye and assessment of its antimicrobial activity

The aim of this study was to investigate whether complexly constituted phenolics extracts from pepper waste may be utilized for the recovery of natural colored preparations.At first, different solvents mixture were compared to determine the best solvent for extraction of phenolic compounds from pepper by-product. The three solvents ethanol, acetone and water were used. The total phenolic content (TPC), the total flavonoid content (TFC) and the relative color strength (K/S) were studied using a simplex-centroid design. Acetone–water (68–32%) with 224mg/L for total phenolic content and acetone–water (61–38%) with 0.446mg/L for total flavonoid content were the best solvent mixtures for the extraction.The colored extract of pepper by-products was applied on woolen fabrics to investigate the dyeing characteristics and antimicrobial efficacy against common human pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. The results indicate that extract can be applied on woolen fabrics to produce colored clothing and textiles with acceptable antimicrobial properties.

COLOR CO-ORDINATES AND RELATIVE COLOR STRENGTH OF REACTIVE DYE INFLUENCED BY FABRIC GSM AND DYE CONCENTRATION

Role of dye concentration as well as fabric GSM on relative color strength and color coordinates were examined by spectral analysis. Spectral analysis of cotton fabric dyed with C.I. Reactive Yellow 145 has recorded maximum absorption at 430nm wavelength by using Kubelka-Munk theory, which allows the prediction of spectral reflectance of colorants in terms of absorption and scattering coefficients at same wavelength. The dyed fabric samples were tested in Datacolor 650(reflectance spectrophotometer) to get the difference in color coordinates (DL*, Da*, Db*, DC* and DH*). This paper focused on the effects of fabric GSM and dye concentration on color coordinates and relative strength of color. The color strength of a dyed fabric is usually expressed by its k/s value. Color strength of dyed samples is relatively increases with the increase of fabric GSM and this value indicates maximum at higher GSM. On the other hand, color coordinates also changed as the changes with fabric GSM and dye concentration. Fabrics became darker when the colorant concentrations increased. Samples showed evidence of more redness and yellowness than the standard. Saturation level of dye also influenced positively in most cases i.e more intensive in higher areal density (GSM) of fabric.

Coloration properties and chemo‐rheological characterization of a dioxazine pigment‐based monodispersed masterbatch

ABSTRACTA dioxazine‐based color pigment was added to a commercial polyamide 6 (PA6) through an extrusion process, in order to prepare monoconcentrated violet masterbatches through different production set‐up. A detailed characterization of the resulting materials was carried out in order to find the best processing parameters combination to optimize pigment dispersion and to reduce the clogging power. The preparation of masterbatches with repeated extrusions markedly reduced the filter pressure value and increased the Relative Color Strength, while filtration did not significantly influence pigment dispersion. Rheological measurements and end‐groups analysis were conducted on the same materials with the aim to evaluate their thermal degradation resistance, and the thermal stability of the compounds was retained even upon three extrusions. Therefore, it can be concluded that a proper optimization of the process parameters could lead to an important reduction of the production waste, increasing the quality of the final product. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41452.

Development and optimisation of a non conventional extraction process of natural dye from olive solid waste using response surface methodology (RSM)

Dyes obtained from different natural sources have emerged as an important alternative to synthetic dyes.In this study, optimisation of natural colorant non-conventional extraction technique from olive waste was investigated using response surface methodology. The combined effects of extraction conditions on total phenolic content (TPC) and relative color strength (K/S) were studied using a three-level three-factor Box–Behnken design. The optimum conditions for dye extraction were found to be 0.14mol/L, 62.11min, 71.23°C and 4.5g for sodium hydroxide concentration, extraction time, temperature, and mass of the waste, respectively.The efficiency of extraction under these optimum conditions was found to be 1133.86mg/L of phenolics and relative colour strength (K/S) equal to 23.22. Further, Fourier Transform Infrared Spectroscopy was used to identify the major chemical groups in the extracted dye.

Optimization of dyeing conditions for Reactive Red 2 on mulberry silk waste/wool blended fabric

Silk and wool are protein fibers due to the presence of amines, carboxylic acid, amide, and other polar groups and therefore possess similar chemical properties. Silk and wool blends are dyed in piece form or as yarn on packages and hanks. Silk is chemically related to wool because the amino groups are integral components of both fiber, thus both can be dyed with the same dyes. The present study was undertaken to study the statistical optimization of Reactive Red 2 dye on mulberry silk waste and wool blended fabric. Optimization is done on the basis of Commission Internationals Del’ Eclairage (CIE) Lab colour space, K/S values (relative colour strength of dyed fabrics) and wash fastness grades

Natural dyeing of fabrics using Quercus robur L. (fruit cups) dye and Punica granatum L. (peel) mordant

Investigation was carried out to study the dyeing quality of Quercus robur L. (fruit cups) and Punica granatum L. (peel) mordant for the dyeing of wool and cotton fabrics. The fabrics were dyed both excluding and including the mordant by adopting different mordanting methods. The efficiency of the dye and mordant combinations was evaluated in terms of percent absorption (%), Colour coordinates (CIELAB), Colour strength/ Relative colour strength (K/S) and fastness properties respectively. Absorption of the dye, colour coordinates, colour strength (K/S) by the wool fabric recorded higher values as compared to cotton fabric. The cotton fabric does not showed much affinity for the dye and mordant combinations and appeared with dull and poor colour shades with lower values of absorption, colour strength and retention grades. However, wool fabric showed beautiful and bright colour shades in different mordanting combinations.

Flame Retardant Properties of Plasma Pretreated/Metallic Salt Loaded Cotton Fabric Before and After Direct Dyeing

In this research work, cotton fabrics were pretreated with low temperature plasma (LTP) and then inoculated in various metallic salts and flame retardancy of cotton fabric was investigated. More polar functional groups were present on the substrate surface after LTP pretreatment. Titanium dioxide (TiO2), zinc sulfate (ZnSO4), lead (II) acetate [Pb(C2H3O2)2], aluminium sulfate [Al2(SO4)3] and silver nitrate (AgNo3) were used as metallic salts. The flame retardancy of the samples was characterized by limiting oxygen index (LOI) and char yield. Good flame retardant activity for Al2(SO4)3 and AgNo3 treated fabrics were achieved, however, the effect of TiO2 and ZnSO4 on flame retardany of cotton fabrics was moderate. It was concluded that, nitrogen plasma pretreatment, improve the flame retardant properties of cotton samples. The plasma treated and Aluminium sulfate loaded cotton fabric sample has a LOI value of 23.3. It shows that, nitrogen plasma pretreatment has synergistic effect on metallic salts for improving the flame retardant properties of cotton samples. In this research work, the dyeability of samples after loading with metallic salts was investigated. Also effect of dyeing on flame retardant properties was studied. The cotton fabrics treated with metallic salts demonstrate an excellent dyeability property. Color intensities of the dyed fabrics were measured by using a UV VIS–NIR Reflective Spectrophotometer, over the range of 200–800 nm. The results showed that, by using silver nitrate as mordant before dying, the relative color strength (K/S values) of the dyed fabrics has been increased. Water drop test and wash fastness determination (ISO 105-C01) were conducted. Also Electronic Crock meter/Rubbing Fastness Tester AATCC 8 was used to determine the color fastness of textiles. We also concluded that dyeing the plasma treated and inoculated cotton fabrics do not have any negative effect on flame retardancy of cotton fabric.