Dyebath pH Research Articles

Eco-friendly and protective natural dye from red prickly pear (Opuntia Lasiacantha Pfeiffer) plant

New natural dye extracted from red prickly pear was used for dyeing wool with different types of mordents. The effect of mordant concentration on the color strength was discussed; the results obtained indicated that the color strength decreases with the increase of mordant concentration. The effect of the dye bath pH, salt concentration, dyeing temperature and dyeing time was also studied. The color strength and the dye uptake have exhibited high values. Good fastness properties of the dyed fabric were achieved.Antimicrobial activity of wool fabric dyed with this dye was tested according to diffusion agent. Test organisms as Escherichia coli, Bacillus subitilus, Pseudomons aeruginosa and Staphylococcus aureus were used and the results indicated that the samples exhibited a high inhibition zone.According to the available literature, this is the first report concerning a natural dye for fabric from fruits of red prickly pear plants.

Effect of pH of dyebath on dyeability of chitosan-treated tussah silk fabric dyed with acid, basic and disperse dyes

Effect of pH of dyebath on dyeability of chitosan-treated tussah silk fabric dyed with acid, basic and disperse dyes

ULTRASONIC ASSISTED ECO-FRIENDLY DYEING OF SILK FABRICS

In recent years, the textile industry proceeds towards creation of new technologies to reduce the energy and water consumption. The use of ultrasonic in textile wet processing is one way to achieve that purpose. The present work investigates the effects of ultrasonic energy on dyeing of silk fabrics with Chlorophyll as a natural dye. Silk fabrics were dyed with Chlorophyll dye in an ultrasonic bath by the conventional exhaustion method. The parameters that affect the dyeing process, such as dye concentration, dye bath pH, salt concentration, and temperature, time and power energy ultrasonic values have been explored. Concentration of tannic acid was also studied as a mordant in the dyeing process. The results show that the color strength as well as fastness properties of the dyed silk fabrics were enhanced on using the ultrasonic technique compared with the conventional method in presence of 5% tannic acid.

Ultrasonic Assisted Dyeing Part I: Dyeing of Acrylic Fabrics Using C.I. Astrazon Basic Golden Yellow GLE

The dyeing of acrylic fabrics using C.I. Astrazon Basic Golden Yellow GLE is studied with both conventional (CH) and ultrasonic (US) techniques. The factors that affect dyeability, such as dye bath pH, US power, dyeing time and temperature, are studied. The colour strength values obtained are found to be higher with US than CH heating. Also, the fastness properties of the dyed fabrics are determined with. A comparative study using x-ray and scanning electron microscope (SEM) that is implemented on samples to explain for the better dyeability of acrylic fabrics with the US method. Dyeing kinetics and the time/dye-uptake isotherms reveal enhanced dye-uptake in the second phase of dyeing. The values of the dyeing rate constant, half-time of dyeing and standard affinity, and US efficiency are calculated and discussed.

Cationization of Cotton Fabric for Dyeing with Natural Anthraquinone Dyes from Fusarium Oxysporum

Two anthraquinone compounds are extracted from culture filtrates of Fusarium oxysporum isolate no. 4, which were previously isolated from roots of citrus trees affected with root rot disease. These anthraquinone compounds were identified as 2- acetyl- 3,8- dihydroxy- and/or 3-acetyl- 2,8- dihydroxy- 6- methoxy- anthraquinone. Dyeing of cationized cotton fabrics with these anthraquinone compounds as natural dyes has been studied. The values of the dyeing rate constant, half-time of dyeing and standard affinity have been calculated and discussed. The results of the dye uptake isotherms of cationized cotton fabrics dyed with these compounds indicate high dye uptake and the standard affinity of cationized cotton fiber is higher. The toxicity assay of culture filtrates as well as anthraquinone pigment extracted from Fusarium oxysporum against root growth (seed germination) of citrus seeds is investigated. Seeds of sour orange are more affected by all tested concentrations of anthraquinone compounds as well as culture filtrates of Fusarium oxysporium than other citrus seeds. Seeds of lime and Cleopatra mandarin are less affected. The effects of dye bath pH, salt concentration, dyeing time and temperature are studied. Color strength and dye uptake exhibit high values. The results of fastness properties of the dyed fabric are good.

Dyeing fine denier polypropylene fibers with phenylazo-β-naphthol-containing sulfonamide disperse dyes

A series of phenylazo-β-naphthol-containing sulfonamide disperse dyes were prepared from C.I. Acid Orange 7 by successive reactions of chlorination and amination, and their chemical structures were characterized by FTIR, 1H NMR, and mass spectrometry. The dyes were applied to coloring of knitted fabrics from fine denier polypropylene fibers by exhaust dyeing and their optimal dyeing conditions, such as dyebath pH, dyeing temperature, dyeing time, and dye concentration were investigated in detail. Then, dye exhaustion, color strength, and color fastnesses of the dyes on the fibers were assessed and summarized. In view of dye exhaustion and color strength of the sulfonamide dyes on fine denier PP fabrics, 90°C was selected as the best dyeing temperature at dye concentration below or equal to 3.0% owf. For achieving higher color strength, 130°C was the better choice when the dye concentration was above 3.0% owf. The sulfonamide dyes, especially secondary sulfonamide dyes, exhibited superior dye exhaustion and color fastnesses to washing, sublimation, and rubbing on fine denier PP fabrics in comparison to C.I. Solvent Yellow 14 bearing the same chromophore but without sulfonamide group.

Applying regression analysis to improve dyeing process quality: a case study

The main purpose of this paper is to propose a regression-based new approach to pH control in open beck dyeing to improve its process quality. Specifically, we examine the current practice of adjusting pH of dye liquor at a large manufacturer of automotive carpets in the United States and point out several drawbacks that lead to substandard products. To properly address the issues, we theorize casual relationships among the key variables in the dyeing process and seek to identify them by using a multiple linear regression model based on the data gathered from actual production dyeings at the company. Our findings show that a dyer should set the pH of the solution in the beck before the dyes are added so that the dyebath pH after the addition of the dyes will be in the target range for best coloring results with minimum or no adjustment. The suggested approach enhances the quality of the dyed carpets, reduces laboratory work required to fix defective products, and renders the operations much more efficient. All of these translate into significant cost savings.

Dyeing of modified acrylic fibers with curcumin and madder natural dyes

Hydrophobic fibers are highly crysta lline and non-polar polymers hence pose a big problem for dyers. Modified acrylic fiber containing different amounts of amidoxime groups as a function of the nitrogen content was obtained and dyed with curcumin and madder natural dyes. The dyeing parameters, such as dye concentration, dye bath pH, salt concentration, temperature, and time and the effect of alum and ferrous sulfate used as mordants were investigated. Compared with the dyeings obtained from modified acrylics, those of blank samples appeared less in color strength values. The color strength was proportional to the nitrogen content of the sample and the maximum value was obtained at pH 2 and pH 5 using madder and curcumin, respectively. The fixation of the dye molecules to the modified acrylic fibers was investigated to show mainly ionic and physical bonds. The washing, perspiration, and rubbing fastness properties for the dyed samples were enhanced by application of alum. The light fastness ratings were also improved using ferrous sulfate especially for the case of the samples dyed with madder.

Sorption Characteristics of Indigo Carmine as a Blue Colorant for Use in One-bath Natural Dyeing

Indigo carmine can be used as model for a blue natural colorant for wool and hair dyeing in a one-bath procedure. The sorption and dyeing properties of indigo carmine on wool are studied as a prerequisite for the successful application in combination with natural dye. To evaluate the suitable conditions for the dyeing process, different pH, dye concentrations and temperatures were studied. The dyeing and sorption characteristics on wool were determined on the basis of spectrophotometry and color measurement. Both high dye sorption and color strength were obtained when dyeing at elevated temperature, e.g. 80°C, and lower pH, e.g. pH 3. However, there is significant potential to apply the dyestuff also at temperatures in the range of 40—60°C and pH values of 4—5. Depending on the dyebath pH the sorption isotherms follow the Langmuir- or Freundlich-type isotherm. At pH 3 and 4 Langmuir isotherms are observed, while at pH 5, 6 and 7 sorption on wool follows the Freundlich isotherm behavior. From the dyeing isotherms the standard affinity (Δµ) of the dyeing step was determined. At pH 3 the heat of dyeing (ΔH) and entropy of dyeing (ΔS) were calculated as 40.22 kJ mol -1 and 0.19 kJ mol-1 K -1, respectively.

Ultrasonic assisted dyeing: Dyeing of acrylic fabrics C.I. Astrazon Basic Red 5BL 200%

The dyeing of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% has been studied with both conventional and ultrasonic techniques. The effect of dye concentration, dye bath pH, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with both techniques were compared. Colour strength values obtained were found to be higher with ultrasonic than with conventional heating. The results of fastness properties of the dyed fabrics were studied. X-ray and Scanning Electron Microscope SEM were carried out on dyed samples using both methods of dyeing to find out an explanation for the better dyeability of acrylic fabrics with (US) method. Dyeing kinetics of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% using conventional and ultrasonic conditions were compared. The time/dye-uptake isotherms are revealing the enhanced dye-uptake in the second phase of dyeing. The values of dyeing rate constant, half-time of dyeing and standard affinity and ultrasonic efficiency have been calculated and discussed.

전자선조사에 의한 폴리프로필렌 섬유의 개질 및 염기성염료의 염착특성

Dyeing properties of hydrophobic polypropylene fibers using cationic dyes were investigated to improve dyeability by electron beam irradiation and sulfonic acid incorporation. The color strength of irradiated polypropylene fibers was examined according to the dyeing conditions including pH of dyebath, absorbed doses, and introduction of functional group to fiber substrate. The best dyeing result was obtained when sulfonic acid group incorporated polypropylene fibers after electron beam irradiation were dyed with cationic dyes at alkaline conditions and 30<TEX>$\sim$</TEX>75kGy irradiation ranges.

홍화 황색소 견섬유에 대한 염색성과 색상

The objective of this study is to investigate the dyeing properties of safflower yellow dye on silk for the standardization of dyeing process and color reproducibility. Yellow colorants were water-extracted from safflower petals, concentrated, and freeze-dried to obtain colorants powder. The effects of dye concentration, dyeing temperature, and pH of dye bath were studied in terms of dye uptake and shade. Fastness to dry cleaning and light was evaluated. Dye uptake increased with raising temperature and brighter and more vivid yellow shade was obtained when dyed at . As colorants concentration increased, dye uptake increased progressively and the shade got darker and deeper. Maximum color strength was obtained at pH 3.5. It was speculated that the adsorption of colorants seemed to occur mainly by hydrogen bonding and physical force at pH 5.5 and by ionic bonding as well as hydrogen bonding below isoelectric point(pH 3.8-4.0). The results of reproducibility test showed acceptable color difference in the range of . Washing fastness was fairly good as 4/5 rating, while light fastness was 2/3 rating.

Parmotrema austrosinence(지의류)를 이용한 직물염색과 키토산 처리에 의한 염색성 향상

국내에서 자라는 지의류의 한 종류인 Parmotrema austrosinence를 채취하여 염액을 제조하고, 제조된 염액을 사용하여 견직물, 나일론직물과 면직물을 염색하였다. Parmotrema austrosinence를 암모니아수에 넣고 발효시켜 얻은 염액을 사용하여 pH를 4, 7, 10으로, 염색온도를 <TEX>$30^{\circ}C$</TEX>, <TEX>50^{\circ}C$</TEX>, <TEX>$80^{\circ}C$</TEX>로 각각 조절한 후 염색을 하였다. 면직물은 견직물과 나일론직물에 비해 염색성이 낮게 나타났다. 면직물의 염색성 향상을 위해 키토산 액으로 처리하고 염색성과 염색견뢰도의 변화를 검토하였다. 염색된 시료들의 염색성은 K/S값, <TEX>${\Delta}E$</TEX>와 Munsell값을 측정하여 평가하였다. 염색된 시료들의 K/S값은 견직물의 경우에는 520nm에서, 나일론직물과 면직물은 480nm에서 최대 흡광파장을 나타냈다. 견직물 염색포의 K/S값은 <TEX>$4.6{\sim}9.3$</TEX>으로 <TEX>$1.0{\sim}2.7$</TEX>인 나일론직물이나 <TEX>$0.8{\sim}1.6$</TEX>인 면직물에 비해 매우 높게 나타나 견직물이 Parmotrema austrosinence 염액에 대해 우수한 염색성을 가짐을 확인하였다. 염색온도가 높아질수록 먼셀 색상값이 red나 yellow red에서 yellow쪽으로 이동하는 색상변화가 나타났다. 견직물의 경우, 염색온도가 <TEX>$50^{\circ}C$</TEX>와 <TEX>$80^{\circ}C$</TEX>일 때의 염색성이 비슷하였으며, 다른 직물의 경우에는 염색온도 상승에 따라 K/S값도 높아졌다. 따라서 지의류를 사용한 적정 염색온도는 견직물의 경우 <TEX>$50^{\circ}C$</TEX>, 다른 직물의 경우 <TEX>$80^{\circ}C$</TEX>임을 확인하였다. 염색된 시료의 먼셀 색상은 견직물에서는 R(red) 영역에서, 나일론 직물에서는 YR(yellow red)-R 영역에서, 면직물은 YR 영역으로 나타났다. 면직물과 나일론직물은 중성 또는 산성염액에서 염색이 잘 되었고, 견직물의 경우는 중성 염액에서의 염색성이 가장 우수하였다. 염색성이 낮게 나타난 면직물은 키토산 가공에 의해 염색성과 염색견뢰도를 향상시킬 수 있음을 확인하였다 염색된 시료들의 일광견뢰도와 세탁견뢰도는 대체로 낮게 나타났으나 드라이크리닝 견뢰도는 4-5급 또는 5급으로 모두 우수하였다. Three fabrics, 100% silk, nylon and cotton each, were dyed with a lichen dye solution prepared by a fermentation method under conditions of varying dyebath pH and temperature. To verify the effect of chitosan on fabric dyeing, the 100% cotton fabric was treated with a chitosan solution before dyeing. The K/S, CIE <TEX>$L^*$</TEX>, <TEX>$a^*$</TEX>, <TEX>$b^*$</TEX>, <TEX>${\Delta}E$</TEX> and Munsell values of the dyed samples were measured. Colorfastness of each sample was also investigated. The maximum K/S value was measured at 520nm wavelength for the dyed silk fabric and at 480nm for the dyed cotton and nylon. The K/S values for the dyed silk fabric were much greater than those of the other fabrics. The dyed silk fabric showed a red tone on the Munsell color system, and the dyed nylon and cotton fabrics a yellowish red tone. Dye affinity to fabrics was better in a neutral or acidic dyebath. As dyeing temperature increased, K/S values increased for the dyed nylon and cotton fabrics but not for the silk. Dyeability of cotton fabrics could improve by Chitosan treatment. As for most natural dyes, colorfastness of all dyed samples was poor. The silk fabric showed an excellent dry cleaning fastness of Grade 5.

Dyeing of wool with natural anthraquinone dyes from Fusarium oxysporum

Two anthraquinone compounds are described which were produced by liquid cultures of Fusarium oxysporum (isolate no. 4), isolated from the roots of citrus trees affected with root rot disease. These anthraquinone compounds are 2-acetyl-3,8-dihydroxy-6-methoxy anthraquinone or 3-acetyl-2,8-dihydroxy-6-methoxy anthraquinone. Dyeing of wool fabrics with these new anthraquinone compounds as natural dyes has been studied. The values of dyeing rate constant, half-time of dyeing and standard affinity have been calculated and discussed. The effect of dye bath pH, salt concentration, dyeing time and temperature were studied. Colour strength values and the dye uptake were high. The results of fastness properties of the dyed fabric were good.

Ultrasonic assisted dyeing. IV. Dyeing of cationised cotton with lac natural dye

The dyeing of cationised cotton fabrics with lac natural dye has been studied using both conventional and ultrasonic techniques. The effects of dye bath pH, salt concentration, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with ultrasonic and conventional techniques were compared. Colour strength values obtained were found to be higher with ultrasonic than with conventional heating. The results of fastness properties of the dyed fabrics were fair to good. Dyeing kinetics of cationised cotton fibre with lac dye using conventional and ultrasonic conditions were compared. The values of dyeing rate constant, half-time of dyeing and standard affinity and ultrasonic efficiency have been calculated and discussed.

Ultrasonic assisted dyeing: III. Dyeing of wool with lac as a natural dye

The dyeing of wool fabrics using lac as a natural dye has been studied in both conventional and ultrasonic techniques. The extractability of lac dye from natural origin using power ultrasonic was also evaluated in comparison with conventional heating. The results of dye extraction indicate that power ultrasonic is rather effective than conventional heating at low temperature and short time. The effects of dye bath pH, salt concentration, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with ultrasonic and conventional techniques were compared. Colour strength values obtained were found to be higher with ultrasonic than with conventional heating. The results of fastness properties of the dyed fabrics were fair to good. Dyeing kinetics of wool fibre with lac dye using conventional and ultrasonic conditions was compared. The time/dye-uptake isotherms are revealing the enhanced dye-uptake in the second phase of dyeing (diffusion phase). The values of dyeing rate constant, half-time of dyeing and standard affinity and ultrasonic efficiency have been calculated and discussed.

Influence of Anionic Dye Sorption Properties on the Color of Wool Top

When wool dyeing with anionic dyes, "right-first-time" production and "batch-to-batch" color reproduction depend on the physicochemical properties of the wool fibers, the sorption properties of the dyes, and numerous technological parameters in the dyeing process. In this research, the effects of two process parameters (pH of dyebath and liquor-to-wool ratio) on dye sorption are investigated during batch dyeing of wool top and, consequently, with regard to color. Dyeing involves four anionic dyes—one acid dye (yellow) and three 1:2 metal-complex dyes (yellow, red, and blue). Dye sorption from unicomponent and bicomponent dyebaths is determined using on-line absorbance measurements, and the color of the dyed samples is evaluated colorimetrically using the CIELAB color system. The results indicate significant differences in the sorptions of the dyes with variations in dyebath pH and liquor ratio, which lead to color differences in wool production.

Fuzzy control of dyebath pH in exhaust dyeing

In textile exhaust dyeing, the control of dyebath pH is a critical factor in order to achieve optimum colour yield and levelness. Conventional controllers have not proved entirely successful in controlling dyebath pH since it is difficult to develop an exact mathematical model for the dyeing process. One method is to apply fuzzy control to the dyeing process. For the fuzzy controller to operate successfully, it is important to understand how the dyeing system responds to given reference pH/time profiles. A dynamic model for the dyeing process has been developed and this allows the fuzzy controller to be fine‐tuned by computer simulation. Results of the control system simulation showed very satisfactory tracking performances of the pH profiles. This provides a starting point for further fine‐tuning of the system under practical dyeing conditions.

Reuse of textile reactive azo dyebaths following biological decolorization.

The objective of this work was to evaluate the feasibility of biological decolorization and reuse of textile reactive azo dyebaths with the goal of developing an in-plant, closed-loop decolorization system leading to water conservation and wastewater minimization. Decolorization of three spent dyebaths was investigated using a suspended-growth, halophilic mixed culture under anoxic conditions. A high rate and extent of color removal ranging from 77 to 90% was achieved. The three azo dyebaths and their decolorization products did not inhibit the halophilic culture. Although single dyeings using the biologically renovated dyebaths as process water resulted in highly reproducible and consistent fabric color shades, pH adjustment of the renovated dyebaths during the dyeing cycle was necessary. The extent of color removal using a biofilm reactor ranged from 86 to 95% during five repetitive dyebath decolorization and reuse cycles without any inhibition and residual color buildup. Repetitive dyeing with the same biologically decolorized dyebath for up to five cycles using a biofilm reactor and dyebath pH adjustment during the redyeing process resulted in almost identical fabric color shades as standard dyeing using fresh water. Excellent reproducibility in fabric color shades was also obtained by using biologically decolorized dyebaths in cross dyeings with different dyeing recipes. To our knowledge, this is the first report on the feasibility of biological decolorization of spent reactive dyebaths using a halophilic mixed culture and the direct reuse of the renovated dyebath as process water in the dyeing process. The results of this study demonstrate that in-plant application of closed-loop dyeing and decolorization is feasible and has the potential to not only decrease wastewater volume and treatment cost, but also minimize water use as well as the discharge of textile pollutants such as salt and dyes.

Developments and trends in radiation curing

Six model dyes and two colourless compounds having different functionality were prepared, and their dyeing properties and the effect on inhibiting wool set and fabric hygral expansion were investigated. It was found that hetero-bifunctional reactive dyes are more efficiently able to bond to wool fibre regardless of dyebath pH than mono-functional (monochlorotriazine) reactive dyes. Also, dyeing wool fabrics with hetero-bifunctional dyes and colourless compounds containing vinylsulphone residues clearly decreased the hygral expansion and inhibited permanent set, when compared to dyeings produced with mono-functional reactive and non-reactive dyes. The improvements in the two physical properties were found to increase with increased reactive dye or reactive compound concentration. Dyes containing a β-sulphatoethylsulphone group diffused more evenly than dyes containing a preactivated vinylsulphone group. It was also shown that the number of sulphonate groups in a dye molecule affected migration properties.