Research on the detection of fabric color difference based on T‐S fuzzy neural network

T‐S fuzzy neural network algorithm is used to establish the mapping relationship from the RGB space to the L*a*b* space, which avoids the complex process of color space conversion. Meanwhile, the block method is adopted to detect color difference of dyed fabric that is wide format and wide viewing angle. Color differences in different regions can be calculated with Color Measurement Committee color difference formula based on T‐S fuzzy neural network. Experimental results are in accordance with the spectrophotometer measurement, which proves that T‐S fuzzy neural network algorithm used in real‐time color detection process is effective and feasible. Workers can make corresponding adjustment on‐line according to the deviation to ensure the quality of fabric color and reduce the loss.     

Ozone treatment of textile effluents and dyes: effect of applied ozone dose,pH and dye concentration

The ozonation of wastewater supplied from a treatment plant (Samples A and B) and dye‐bath effluent (Sample C) from a dyeing and finishing mill and acid dye solutions in a semi‐batch reactor has been examined to explore the impact of ozone dose, pH, and initial dye concentration. Results revealed that the apparent rate constants were raised with increases in applied ozone dose and pH, and decreases in initial dye concentration. While the color removal efficiencies of both wastewater Samples A and C for 15 min ozonation at high ozone dosage were 95 and 97%, respectively, these were 81 and 87%, respectively at low ozone dosage. The chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal efficiencies at several ozone dose applications for a 15 min ozonation time were in the ranges of 15–46% and 10–20%, respectively for Sample A and 15–33% and 9–19% respectively for Sample C. Ozone consumption per unit color, COD and DOC removal at any time was found to be almost the same while the applied ozone dose was different. Ozonation could improve the BOD₅ (biological oxygen demand) COD ratio of Sample A by 1.6 times with 300 mg dm^?3 ozone consumption. Ozonation of acid dyes was a pseudo‐first order reaction with respect to dye. Increases in dye concentration increased specific ozone consumption. Specific ozone consumption for Acid Red 183 (AR‐183) dye solution with a concentration of 50 mg dm^?3 rose from 0.32 to 0.72 mg‐O₃ per mg dye decomposed as the dye concentration was increased to 500 mg dm^?3. © 2002 Society of Chemical Industry     

Effect of reactive dyeing on the UV protection affected by knitted fabric made from different types of cotton fibre

In this study, 100% cotton knitted fabrics made from combed cotton and combed pima cotton were dyed with reactive dye, with different dye concentrations. Colour properties such as CIE L*a*b* values as well as dyeing uniformity of the dyed fabrics were measured. The relationships between colour properties and the ultraviolet protection afforded by cotton knitted fabrics were investigated. Experimental results revealed that dye concentration is the most important factor. In addition, only L* values have a direct mathematical relationship with the ultraviolet protection factor; a* and b* values and dyeing uniformity were not found to have a significant correlation with ultraviolet protection factor values. Meanwhile, knitted fabric made from combed cotton fibre has better ultraviolet protection performance than fabric made from combed pima cotton fibre.     

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse dyes

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse red dye was studied in the temperature range 283–363 K. 1‐vinyl 2‐pyrrolidone (NVP), acrylic acid (AA) or their mixture was used to graft poly(ethylene terephthalate) (PET) fabric. The effects of pH of the dye solution, graft yield (GY), dyeing time (t), dye concentration (C), and dyeing temperature (T) on the colour difference (CD) of PET fabric were studied. The best dyeing condition was achieved at pH 5.5. CD increases linearly with the increase in GY, with slopes depending on the type of grafted copolymer. CD increased rapidly as the dyeing time increased; this was followed by a relatively slow dyeing rate within a few minutes. The initial dyeing rate (R) was found to increase with an increase in C and T. The dyeing rates for all grafted samples followed 0.35‐order kinetics and are temperature‐independent. Average activation energy 9.26 kJ mol^?1 is calculated for the dyeing process and is independent of the fabric treatment. Pre‐exponential rate constants 1976, 1839, and 1579 (CD/GY) s^?1 were calculated for dyeing PET samples grafted with AA/NVP mixture, NVP and AA, respectively, while 1074 CD s^?1 was evaluated for carrier dyeing of ungrafted fabric. Analysis of the kinetic parameters and the dyeing mechanism revealed that dyeing PET fabric was diffusion‐controlled. Grafting PET fabric improved significantly the dyeing affinity of the DR dye over ungrafted samples dyed in solutions containing a carrier. Copyright © 2005 Society of Chemical Industry     

Investigation of a homogeneous activating ozonation method in the rinsing procedure of cotton fabric dyed with reactive dye

The textile dyeing process requires the consumption of large quantities of water, which includes huge amounts of coloured wastewater. Usually the rinsing of dyed fabric and the treating of the dyeing house wastewater are separated. The two independent processes not only increase the difficulty of wastewater treatment but also increase the costs of the treatment. In this paper, the ozone/tetraacetylethylenediamine active oxidation technology was employed to rinse dyed fabric and to decolorise the rinsing wastewater simultaneously. The effects of the rinsing conditions on the decolorisation ratio and the chemical oxygen demand Cr value of treated wastewater, and the K/S value, colour difference, tensile strength and fastness of dyed samples were investigated. The results indicated that the decolorisation ratio of the rinsing effluent was greater than 80% and the chemical oxygen demand Cr value decreased more than 58% by the ozone/tetraacetylethylenediamine rinsing process compared with that of traditional rinsing processes. Furthermore, the curve of decolorisation kinetics was in good agreement with a pseudo‐first‐order kinetic model. In addition, the decolorisation mechanism was also discussed after ultraviolet–visible and ultra performance liquid chromatograph–mass spectrometry analyses of the degraded dye molecule.     

Color evaluation of wool fabric dyed with Rhizoma coptidis extract

Berberine is the only cationic colorant of natural plant dyes, which lies in the roots of Rhizoma coptidis and stems of phellodendron. In this study, wool fabric was dyed with the extracts of R. coptidis. Color evaluation was characterized with ΔE, L*, a*, b*, c*, H⁰, K/S. Effects of mordant, extraction concentration, pH value of dye bath, and treatment temperature on color values were studied. Results indicated that wool fabrics dyed with mordant, or at higher temperature, or in alkali solution possessed deeper shades and darker colors. And the wool fabric showed good antibacterial property after dyeing with R. coptidis extracts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3376–3380, 2006     

Afterclearing of disperse dyed polyester with gaseous ozone

The efficiency of ozone treatment for the clearing of disperse dyed polyethylene terephthalate fibres has been examined. The ozone treatment for the clearing of the dyed samples was performed by blowing the ozone gas from the ozone generator on to the wet fabric samples. The results indicated that 3‐ and 5‐min ozonation times were appropriate to achieve comparable wash fastness results with conventional reduction clearing without significant colour differences (ΔE* value) for the samples dyed with CI Disperse Yellow 23 and CI Disperse Blue 79, respectively; however, the ozonation time had to be increased to 15 min for CI Disperse Red 82. Tensile strength tests and scanning electron microscopy analysis indicated that the ozone treatment did not cause any severe damage to the fabrics. Ozone treatment for the afterclearing of disperse dyed polyester fabric can lead to energy and time savings and environmental load reduction when compared with conventional reduction clearing. This study tested a new method of ozone application for clearing of disperse dyed polyester by blowing ozone directly on to the fabric samples. This new method of application has the advantage of being readily adoptable for continuous treatment lines and lower water consumption.     

Ozone treatment process for the removal of pharmaceuticals and personal care products in wastewater

This study investigated the degradability of pharmaceuticals and personal care products (PPCPs) by ozonation for the treatment of secondary effluent of a municipal wastewater treatment plant. A set of experiments were conducted in a laboratory using a pilot-scale process consisting of three flow-through reactors in series, by varying the ozone dose (1–9 mg L^?1), the hydraulic retention time (5–15 min), and the concentration of ozone injected into the reactors (14–42 mg L^?1). Thirty-seven PPCPs were detected in the secondary effluent, which belongs to the use categories of antibiotics, analgesics, antiarrhythmic agents, anticonvulsants, vasodilators, lipid modifying agents, anti-itch drugs, anti-psychotic drugs, insect repellents, bronchodilators, diuretics, peptic ulcer drugs, NMDA receptor antagonists, antifungal drugs, antimicrobial drugs, and antineoplastic agents. These PPCPs were broadly classified into five groups ranging from “sensitive” to ozone (O₃) or “unstable” in the ozonation process, to the group of “insensitive” to O₃ or “very stable” in the ozonation process. These groups are based on the PPCP concentrations after the ozone treatment and their limit of detection (LOD). Furthermore, this study examined comparatively the effects of the ozone dose, the retention (reaction) time, and the concentration of O₃ supplied to the reactors on the degradability of the PPCPs.     

γ-Radiation induced graft copolymerization of N-phenyl- and N-p-hydroxyphenyl maleimide onto cotton fabrics

The graft copolymerization of N-phenylmaleimide and its p-hydroxy derivative onto cotton fabric using γ-radiation was studied. The effects of monomer concentration, dose rate, and irradiation time have been investigated. The surface topology, the x-ray diffraction, and the thermal stability of the modified fabric also were studied. In addition, the dyeing characteristics of the grafted fabrics when dyed with basic dyes together with the color fastness of these dyes towards UV radiation were investigated.     

Effect of the water content of padded cotton fabrics on reactive dye fixation in the pad-steam process

A series of padded cotton fabrics with various water contents were obtained through vacuum dehydration. The effects of the water content on the fabric temperature variation during steaming, the colour properties, and the dye fixation rate (%F) were investigated. Dye distribution in the dyed cotton fibres was assessed. The influences of steaming time and sodium carbonate concentration on K/S value and %F of the dyed fabrics with low water content were also evaluated. The results indicate that reducing the water content of the padded cotton fabric to around 25.0% prior to steaming was favoured for reactive dyeing. The temperature of the wet fabric rose rapidly, the K/S value and %F were enhanced, and in addition the dye penetration into the dyed cotton fibres was sufficient. However, for padded fabrics with extraordinarily low and high water contents (e.g. 1.4% and 70.9% respectively), both the K/S value and %F were decreased. Furthermore, a white core phenomenon was evident for the fibres of the dyed fabric with a water content of 1.4%. Variation in the L^* values was in line with the K/S values as the fabric water content varied. As expected, steaming time and sodium carbonate dosage can also affect reactive dye fixation greatly and should be determined accordingly for dyeing cotton fabric with low water content.     

Shade darkening effect of polyorganosiloxane modified with amino and hydroxy groups on dyed polyester microfiber fabric

The novel polyorganosiloxane material S‐101 modified with amino and hydroxy groups is synthesized. Shade darkening effect of modified polyorganosiloxane on dyed polyester microfiber fabric is investigated by reflectance spectrum, color yield (K/S), and the color differences (ΔE). The colorimetric data of CIELAB is discussed. The results show that the novel material of silicone polymer modified with amino and hydroxy groups has excellent shade darkening effect on dyed polyester microfiber fabric. The rates of the color yield increase (I%) of all dyed fabric with four dyes (Disperse Yellow S‐4RL, Red GS, Blue 2BLN, and Black SF‐R) exceed 10%. The shapes of the reflectance spectra curves of the dyed fabrics before and after treated with S‐101 are not noticeable change. The dyed fabrics with the polymer have not significant effect on the wash fastness and wet rubbing fastness. The low reflectance thin film on dyed fabrics is formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Optimization of dyeing of wool with madder and liposomes by central composite design

The preparation and production of multilamellar liposomes from Soya lecithin with 75% phosphatidylcholine were carried out and the behavior of liposomes in dye‐bath at different temperature, time, and concentration were examined. It was found that liposomes with concentration of below 3% o.w.f. (on weight of fabric) in the dye‐bath increases the amount of K/S for the samples dyed at 85°C or below 85°C for 60 min. Dyeing of wool at higher temperature and longer time with higher concentration of liposomes reduces the color strength. The results showed that using 2% o.w.f. of liposomes in dye‐bath at 85°C for 60 min improves the K/S. The Central Composite Design is used for the experimental plan with three variables on the results of color strength. Statistical analysis confirms the optimum conditions obtained by the experimental results. It was also found that wash, light, wet and dry rub fastness properties of samples dyed with madder including liposomes have not changed significantly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Colour stripping of reactive‐dyed cotton by ozone treatment

Trials have been carried out to investigate the efficiency of ozone treatment in the colour stripping of reactive‐dyed cotton fabrics. The trials were performed on a specially designed apparatus to inject ozone gas into the liquor passing through a perforated beam with fabric rolls on it, just like a beam dyeing machine with ozone venturi injection. Conventional reductive colour stripping was applied as the control treatment, and ozone treatment was applied for three different application times (15, 30, and 45 min). Trials were performed with seven selected reactive dyes having various chromophores and reactive groups. The results indicate that 45 min ozone treatment yielded the best colour stripping results among the three application times. Furthermore, the colour stripping percentages of the 45 min ozone treatment were higher for four of the tested dyes, the same for one of the tested dyes, and lower for two of the tested dyes compared with the control treatment, which consisted of conventional reductive colour stripping. Colour stripping of 90% and above was achieved for all samples of the 45 min ozone treatment. The chemical oxygen demand values of the colour stripping baths were compared: the average value of the 45 min ozone application baths was 105 mg l^?1, and it was 1993 mg l^?1 for the conventional reductive treatment baths. Consequently, a reduction in chemical oxygen demand of almost 94% was achieved by ozone treatment compared with conventional reductive treatment. The strength values of the fabrics after the respective treatments were similar, with a difference of only 3%.     

Preparation and properties of Fe(II)‐ion‐sensitive colour‐changing fabric

Textile fabrics were dyed with complexometric indicators (ionochromic dyes) to develop Fe(II) ionochromic fabric. Three kinds of ionochromic dye were used to dye silk fabric, and they were evaluated for colour changes triggered by Fe(II) solution. The K/S values and photos of the fabrics were then recorded. It was found that 1,10‐phenanthroline was the most suitable ionochromic dye in these dyes. Colour change from white to red could be clearly seen when 1,10‐phenanthroline‐dyed silk fabric was triggered by Fe(II) solution, but it showed no colour change when triggered by Cu(II), Mg(II), or Ca(II) solution. Moreover, 1,10‐phenanthroline‐dyed nylon, polyester, and cotton fabrics showed no obvious colour changes after triggering by Fe(II) solution. Ion concentration, pH value, and reaction time could affect the colour changes. When triggered by 8 mg l^?1 of Fe(II) solution at neutral pH for about 15 min, the ionochromic fabric showed a clear colour change. In addition, three coloured fabrics in green, blue, and yellow were also dyed with 1,10‐phenanthroline. It was found that they could also show clear colour changes when triggered by Fe(II) solution. These ionochromic fabrics may find broad application in many fields, such as Fe(II) detection, magic toys, anticounterfeiting materials, and bionic silk flowers.     

Decolorisation by Bacillus flexus of exhausted dyebaths containing CI Acid Red 249 and their reuse for wool dyeing

A dyebath containing left-over CI Acid Red 249 after dyeing of wool was completely decolorised using an isolated bacteria Bacillus flexus. Optimisation was carried out by varying the pH, temperature, dye concentration, and microbial loading. Complete decolorisation of a 50 mg l⁻¹ dye solution was achieved in 8 h at pH 7 and 37 °C with 10% v/v loading of the bacteria. The decolorised bath was utilised for dyeing of wool fabric with the same dye at 5% shade. This cycle of dyeing–decolorising–dyeing was repeated 5 times. The evaluation of dyed fabric was done using K/S, colour values, and fastness to light and washing. Comparison of a sample dyed with the conventional exhaust process showed that the dyeing quality is not affected for all five successive reuse cycles. The results are important from the viewpoint of reducing water consumption and chemicals.     

Synthesis of reactive disperse dyes containing halogenated acetamide group for dyeing cotton fabric in supercritical carbon dioxide

A series of reactive disperse dyes incorporating halogenated acetamide group were synthesized and applied to dye cotton fabric in supercritical carbon dioxide (scCO₂). Dyeing experiments were conducted in scCO₂ with dye concentration of 0.5% owf (% on weight of cotton fabric), varying from 80 to 120 °C, for 1–3 h at a constant pressure of 200 bar. The results showed that the color strength of dyed cotton fabric increased favorably when increasing temperature and time. The color characteristics were studied as well in terms of the reflectance spectra. And the color fastness to washing and rubbing were also reasonably good.     

Substitution of Reduction Clearing Step by Ozone Treatment at Disperse Dyeing of Polyester

The effectiveness of ozone treatment for the afterclearing of disperse dyed poly (ethylene terephthalate) (PET) fibers has been examined. Two types of disperse dyed PET samples were selected among commercial mass production range of Akbaslar textile mill. The reduction clearing procedure applied during mass production was taken as the reference reduction clearing treatment; these reference samples were taken after dyeing and reduction clearing processes at the mill. Samples of disperse dyed PET were also taken before reduction clearing in order apply ozone treatment in the laboratory as the tested afterclearing method. Color and wash-fastness properties of the reduction cleared and ozone treated fabric samples were compared and reported. Results indicated acceptable color and wash-fastness results comparable to those of reduction cleared samples for ozone treated samples. The success of ozone treatment for the black dyed PET sample at 7.0% depth of shade was especially outstanding. Ozone treatment was applied in cold water without addition of any chemicals for very short treatment times when compared to conventional reduction clearing. Ozone treatment created substantial energy and chemical savings as well as lower environmental impact.     

Establishment of a color tolerance for yarn-dyed fabrics from different color-depth yarns

Yarn-dyed fabric is often woven from warp and weft yarns in the same color depth to ensure a uniform color appearance. The difference in color depth between warp and weft tends to result in the uneven color of the yarn-dyed fabric. This article aims to establish a color tolerance for yarn-dyed fabric that can be woven with a qualified color appearance but from the warp and weft yarns in different color depths. A total of 27 yarn-dyed fabric samples in three color series (red, yellow, and blue) were evaluated by using the yarn-dyed fabric from warp and weft yarns in the same color depth of 2% (on weight of fabric, owf) as the standard. Visual assessment and instrumental measurement of color were carried out to establish the color tolerance ellipse that was defined as CMC (Color Measurement Committee) color differences (2:1) of no more than 1.00. It was found that the color strengths (K/S) and color differences (ΔE_CMC(2:1)) of these fabric samples for each color series had linear relationships with the color depths of warp and weft yarns. The color tolerance ellipses indicated that, even though the warp and weft yarns had an apparent color difference, they could be woven in fabrics with relatively uniform color appearance and meet the requirements for yarn-dyed fabric. This work provided valuable insight into the production of qualified yarn-dyed fabrics from unqualified dyed yarns.     

Vapor phase dyeing of synthetic fibers with disperse dyes

Dyeing of synthetic fibers by the heat transfer process of disperse dye vapors is performed by contacting white receptor polyester or polyamide fabric with other dyed polyester fabrics (donor) under the influence of heat. The dye vapours flowing away will diffuse across the very slight air gap enclosed between the inner donor and receptor surfaces under the applied pressure. It is found that the dye uptake by the receptor fabric is dependent on the original dye content of the donor fabric, transfer temperature and dwell time. The released dye from the donor fabric under the influence of heating is found to be dependent on the original dye content of the donor fabric as well as the transfer temperature. The efficiency of the dye transfer is also attributed to the original shading of the donor fabric. Evaluation of the imparted colors on the receptor fabric (polyester, polyamide) obtained by heat contact with the same donor fabric showed visually the same colour level up to the 13th run. Thermodynamic interpretation of the standard affinity (Δu⁰) and heat of dyeing (ΔH⁰) as well as the partition coefficient of the dye show that the dyeing process has an exothermic character. The rate controlling step in this dyeing process is found to be dependent on the diffusion of the dye vapors into the fiber phase.     

The use of ozone to decolorize residual direct paper dyes in kraft paper machine whitewater

Production of colored kraft papers results in strongly colored paper machine spent Whitewaters (ww). The residual dyes prevent efficient recycle of the ww and necessitate periodic system cleanings. Many of the dyes are not adsorbed or degraded by biological effluent treatment and therefore discolor receiving waters. Ozone was tested as a bleaching agent for 15 direct paper dyes added at typical residual levels to kraft mill ww. These dyes included azo, polyazo, stilbene, benzothiazole and phthalocyanine direct dyes commonly used in Canadian dyed paper production. Ozone charges of 15 ‐100 mg/L rapidly bleached most of the dyes, although a few of the yellow stilbene and azo dyes were quite resistant. The efficiency of ozone‐mediated residual dye bleaching was altered substantially by the pH, the ww concentration, and the target dye's chemical structure. Preozonation of residual dye‐containing ww greatly decreased the color conferred to bleached kraft pulp fibers added to the ww. Thus, ozonation should permit much more ww recycle (less effluent) when changing colors on the paper machine. Depending on the availability of oxygen or ozone in a mill, and local ozone economics, ozone may be the most efficient, cost‐effective way to improve ww quality, increase ww recycle and minimize effluent color problems and environmental impact.