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Dyeing
Kinds of Dyeing Terms modified by Dyeing Selected AbstractsPotential Applications of Oxidoreductases for the Re-oxidation of Leuco Vat or Sulfur Dyes in Textile DyeingENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2008F. Xu Abstract Conventional textile dyeing by vat and sulfur dyes includes reduction and re-oxidation steps (with chemical reductants and oxidants), so that the insoluble dyes can be solubilized in the dyeing solution, adsorbed by the fabric, and fixed onto the dyed fabric. The treatments often involve hazardous chemicals, expensive catalysts, or conditions that are suboptimally effective, energy-intensive, caustic, or polluting. Improving these steps with enzyme technology could be of significant interest in terms of better dyeing, handling of hazardous chemicals, disposal of waste, or production economy. The idea of an enzymatic re-oxidation step for vat and sulfur dyeings was tested under simplified laboratory conditions. Selected vat and sulfur dyes, including Vat Blue,43, Vat Orange,7, Vat Green,3, Vat Orange,2, Vat Red,13, Vat Yellow,2, and Sulfur Black,1, were first chemically reduced. The reduced (leuco) dyes were then re-oxidized by aerated buffer solutions or H2O2, in the presence or absence of an oxidoreductase, selected from seven laccases from Myceliophthora thermophila, Scytalidium thermophilum, Coprinus cinereus, Trametes villosa, Rhizoctonia solani, Pycnoporus cinnabarinus, Botrytis cinerea, a bilirubin oxidase from Myrothecium verrucaria, and a heme peroxidase from Coprinus cineresu. It was shown that the enzymes were able to catalyze and accelerate the re-oxidation of the reduced dyes, even when they were adsorbed on cotton fabric, by dissolved air (O2) or H2O2. Small redox-active mediators could facilitate the enzymatic re-oxidation. For Sulfur Black,1, a higher conversion of the leuco dye was achieved with laccase-catalyzed re-oxidation. The further development of this potential enzyme application is discussed. [source] Dyeability improvement of polyester pretreated with some alkoxidesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008A. Bendak Abstract The influence of some alkoxides in alcoholic media, having various dielectric constants, on the physical and mechanical properties was thoroughly studied in a previous work to attain silk-like polyester fibers. In this investigation, the dyeability behavior of this silk-like polyester is tried. Both immersion and padding techniques are applied in the treatment. The dyeability of the pretreated polyester fabric with disperse dyes shows some progressive improvements with lowering the dyeing temperature and/or decreasing the time of dyeing attained. Ethoxide is found to be more effective in enhancing the dyeability of polyester fabric than either methoxide or propoxide. Dyeing of the pretreated polyester fabric at the boil without using carriers or conducting high temperature/high pressure dyeing is also possible. Washing and crocking fastness are relatively enhanced. Physicochemical investigations of the dyeing process and a mathematical analysis for evenness are given. A decrease in the half dyeing time and an increase in the rate of dyeing of the pretreated polyester as compared with the untreated one are noticed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Dyeing and finishing of lyocell union fabrics: an industrial studyCOLORATION TECHNOLOGY, Issue 4 2010H D Joshi Lyocell union fabrics, namely lyocell/silk and lyocell/polyester fabrics, were woven in different fabric constructions and dyed with reactive dyes, acid dyes and a disperse dye. The resulting dyed fabrics were given a resin finishing treatment and their wash fastness was measured. With appropriate dye selection and control of dyeing conditions, some bright solid shades and effective cross-dyed shades were obtained. The dyed and finished fabrics had a smooth, lustrous handle, ideal for lightweight garments. [source] Dyeing and fastness properties of phthalimide-based alkali-clearable azo disperse dyes on poly(ethylene terephthalate)COLORATION TECHNOLOGY, Issue 6 2009Joonseok Koh The properties of a series of phthalimide-containing azo disperse dyes and azo dyes with N -methyl phthalimide moieties in their diazo component were investigated and compared when used to colour polyethylene terephthalate. The N -substitution of the phthalimide gave a hypsochromic effect on the colour change and better colour yields on poly(ethylene terephthalate) fabrics, probably because of the electron-donating property of the methyl group and the higher hydrophobicity of phthalimide-containing azo dyes compared with those containing phthalimide moieties. The results show that phthalimide-based azo disperse dyes have excellent dyeing fastness properties and that high wash fastness can be achieved using alkali clearance. This alternative clearance method is important for reducing the environmental impact of the dyeing process by replacing reductive clearing and, in particular, by removing the need for sodium hydrosulphite, which creates a high biological oxygen demand when released in conventional disperse dyeing effluent and which generates aromatic amines. [source] Dyeing of cotton with a bifunctional disulphide bis(ethylsulphone-sulphatoethylsulphone) disazo reactive dyeCOLORATION TECHNOLOGY, Issue 5 2005Y A Youssef A new bifunctional disazo reactive dye of a temporarily high molecular structure based on a disulphide bis(ethylsulphone-sulphatoethylsulphone) reactive system was synthesised and applied to cotton fabric. This dye displayed good primary exhaustion under different neutral exhaustion conditions. The results assessed for the alkaline exhaust dyeing indicate that the disulphide bis(ethylsulphone-sulphatoethylsulphone) dye showed higher exhaustion and fixation values compared to those obtained with the commercial CI Reactive Black 5. The fastness properties of the disulphide dye were similar to those of the commercial dye. Received: 24 March 2005; Accepted: 15 June 2005. [source] Modification of silk with aminated polyepichlorohydrin to improve dyeability with reactive dyesCOLORATION TECHNOLOGY, Issue 2 2007Xie Weibin Reactive dyes have almost complete exhaustion and ideal fixation on aminated polyepichlorohydrin pretreated silk without addition of salt or alkali. The effects of varying pretreatments and dyeing conditions were studied. The dyeing behaviour of CI Reactive Red 15 on modified silk under pH 6 was investigated. Dyeings of modified silk showed good wash fastness, dry and wet rub fastnesses as well as light fastness. The quality of the dyed silks obtained after pretreatment was shown to be satisfactory and the dyeing effluent was less polluted. [source] Quaternary reactive dyes containing a thioether-ethylsulphone group.COLORATION TECHNOLOGY, Issue 6 2003Part 2; Application methods for the dyeing of nylon A member of the new series of cationic reactive dyes containing a thioether-ethylsulphone grouping referred to in Part 1 of this series has been applied to nylon at pH 3,10. The dye is water soluble and shows excellent substantivity for nylon 6.6 when dyed at the boil at pH 8,10. Under alkaline conditions, gradual ,-elimination back to the vinylsulphone dye occurs and covalent bond formation quickly takes place with the fibre; the higher the pH the more rapidly this occurs. Dyeings carried out at pH 10 showed very good brightness and levelling, together with good wash fastness. The light fastness of dyeings at moderate depth was 4,5 on the Blue Wool scale. [source] p -Phenylenediamine sensitization is more prevalent in central and southern European patch test centres than in Scandinavian: results from a multicentre studyCONTACT DERMATITIS, Issue 6 2009Jacob Pontoppidan Thyssen Background:, Positive patch test reactions to p -phenylenediamine (PPD) are common. PPD is used in oxidative hair dyes and is also present in dark henna temporary ,tattoos'. Cross-sensitization to other contact allergens may occur. Because subjects sensitized to PPD are at risk of clinically severe reactions upon hair dyeing, there is a need for ,current' prevalence data on PPD sensitization. Objectives:, To compare PPD patch test results from dermatitis patients tested between 2003 and 2007 in 10 European patch test centres and to analyse the causes and determine relevance of positive PPD patch test reactions. Materials:, Patch testing was performed using PPD (1% free base in petrolatum from Trolab (Almirall Hermal GmbH, Reinbeck, Germany) or Chemotechnique (Malmö, Sweden), equivalent to 0.090 mg/cm2 in the TRUE® test from MEKOS Laboratories AS). Statistical analysis was performed using the chi-squared test. Results:, The weighted average prevalence was 4.6% among 21 515 patients. PPD sensitization occurred more often in centres located in Central and Southern Europe than in Scandinavian centres (odds ratio = 2.40; 95% confidence interval = 2.07,2.78). The overall proportion of positive patch test reactions to PPD that were registered as being of either current or ,past' relevance was high (weighted average 53.6% and 20.3%, respectively). Consumer hair dyeing was the most prominent cause of PPD sensitization (weighted average 41.8%). Furthermore, occupational hair dye exposure (10.6%) and cross-sensitization to textile dyes (12.6%) were frequently reported. Conclusions:, PPD sensitization caused by exposure to hair dyes is frequent and remains a present problem for patients visiting contact dermatitis clinics, especially in patch test centres located in Central and Southern Europe. [source] Allergic contact dermatitis from hair dye and development of lichen simplex chronicusCONTACT DERMATITIS, Issue 1 2004Won Young Chey Those who dye their hair frequently manifest allergic contact dermatitis (ACD) from p -phenylenediamine (PPD)-containing hair dye. PPD is known to be the most frequent sensitizer in hair dye, but there has been no documentation of this sensitizer having a role in chronic dermatologic conditions. Our department experienced a case of a 62-year-old woman with lichen simplex chronicus (LSC), who complained of aggravation after hair dyeing and made such an association. We conducted a prospective and retrospective study to further evaluate the clinical associations between the two. In our prospective study, patch testing was performed in selected patients who regularly carried out hair dyeing and also had clinical manifestations of LSC. Also a retrospective examination was conducted in cases where patch testing had been performed with PPD in the past for suspected ACD and further selected cases with concurrent LSC and/or other neurodermatitis. 11 and 14 patients in our prospective and retrospective study, respectively, presented with both LSC and positive findings to PPD. 5 (45.5%) and 4 (28.6%) patients in our prospective and retrospective study showed clinical relevance from clinical improvement after stopping use and rechallenge. We report several cases of patients diagnosed as having LSC and/or prurigo nodularis who showed clinical improvement after discontinuing the use of hair dye. The suggestion can therefore be made that hair dye could be a possible aetiologic agent causing LSC in those using hair dyes. [source] Potential Applications of Oxidoreductases for the Re-oxidation of Leuco Vat or Sulfur Dyes in Textile DyeingENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2008F. Xu Abstract Conventional textile dyeing by vat and sulfur dyes includes reduction and re-oxidation steps (with chemical reductants and oxidants), so that the insoluble dyes can be solubilized in the dyeing solution, adsorbed by the fabric, and fixed onto the dyed fabric. The treatments often involve hazardous chemicals, expensive catalysts, or conditions that are suboptimally effective, energy-intensive, caustic, or polluting. Improving these steps with enzyme technology could be of significant interest in terms of better dyeing, handling of hazardous chemicals, disposal of waste, or production economy. The idea of an enzymatic re-oxidation step for vat and sulfur dyeings was tested under simplified laboratory conditions. Selected vat and sulfur dyes, including Vat Blue,43, Vat Orange,7, Vat Green,3, Vat Orange,2, Vat Red,13, Vat Yellow,2, and Sulfur Black,1, were first chemically reduced. The reduced (leuco) dyes were then re-oxidized by aerated buffer solutions or H2O2, in the presence or absence of an oxidoreductase, selected from seven laccases from Myceliophthora thermophila, Scytalidium thermophilum, Coprinus cinereus, Trametes villosa, Rhizoctonia solani, Pycnoporus cinnabarinus, Botrytis cinerea, a bilirubin oxidase from Myrothecium verrucaria, and a heme peroxidase from Coprinus cineresu. It was shown that the enzymes were able to catalyze and accelerate the re-oxidation of the reduced dyes, even when they were adsorbed on cotton fabric, by dissolved air (O2) or H2O2. Small redox-active mediators could facilitate the enzymatic re-oxidation. For Sulfur Black,1, a higher conversion of the leuco dye was achieved with laccase-catalyzed re-oxidation. The further development of this potential enzyme application is discussed. [source] Color simulation method for accurate prediction of resulting dyed hair colorINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2007T. Takahashi When choosing hair dyes, it is natural for the user to assume that the final hair color will resemble the color indicated on the product container or color chart. Often, however, the result is quite different. The ability to accurately predict resulting hair color after dyeing is essential, but not easy to attain because hair varies significantly from person to person. In this paper, a new method for predicting the dyed hair state is proposed. Our method is based on a model, where the observed final color consists of contribution from three layers of the hair structure: a melanin-containing layer, a bleached layer and a pigment-colored layer. A method for predicting the final color from responses in each layer is introduced. In this method, response formulae for each layer are derived from the energy balance, and the predicted hair color after dyeing is obtained by calculating the each equation assuming that the hair state before dyeing is solely because of the contribution from the melanin-containing layer. In addition, a small measuring apparatus utilizing this prediction method was developed and the effectiveness of our method demonstrated by data obtained before and after the hair dyeing. [source] Possibilities of polymer-aided dyeing of cotton fabric with reactive dyes at neutral pHJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010B. J. Agarwal Abstract Water-soluble polymers have versatile application, viz., water-soluble polyacrylates have been widely used in the reactive dyeing of cellulosic fibers and the related soaping as an important component of the leveling and washing agent. In this article, one such water-soluble polymer, polyacrylic acid has been synthesized, characterized, and applied in conjunction with various types of reactive dyes, namely triazinyl, vinyl sulfone, high exhaustion, and bifunctional reactive dyes, along with crosslinking agents, namely glycerol 1,3-dichlorohydrin and hexamethylene tetramine-hydroquinone, respectively. One of the crosslinking agents (the former one) has been synthesized in the laboratory. Crosslinking agent is necessary to adhere the dye molecule onto the cellulose macromolecule. Different process sequences have been formulated and explored for dyeing purpose. All such dyeings were carried out at neutral pH. The dyed samples were assessed through color strength in terms of K/S values and their fastness properties were assessed by standard methods. All such dyeings were compared with conventional dyed samples. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Dyeability improvement of polyester pretreated with some alkoxidesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008A. Bendak Abstract The influence of some alkoxides in alcoholic media, having various dielectric constants, on the physical and mechanical properties was thoroughly studied in a previous work to attain silk-like polyester fibers. In this investigation, the dyeability behavior of this silk-like polyester is tried. Both immersion and padding techniques are applied in the treatment. The dyeability of the pretreated polyester fabric with disperse dyes shows some progressive improvements with lowering the dyeing temperature and/or decreasing the time of dyeing attained. Ethoxide is found to be more effective in enhancing the dyeability of polyester fabric than either methoxide or propoxide. Dyeing of the pretreated polyester fabric at the boil without using carriers or conducting high temperature/high pressure dyeing is also possible. Washing and crocking fastness are relatively enhanced. Physicochemical investigations of the dyeing process and a mathematical analysis for evenness are given. A decrease in the half dyeing time and an increase in the rate of dyeing of the pretreated polyester as compared with the untreated one are noticed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effect of textile waste water on the spermatogenesis of male albino ratsJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2003R. S. Gupta Abstract Textile waste water released from dyeing and printing industries situated in Sanganer, Jaipur (India), brought about inhibition of spermatogenesis in male rats. Water analysis showed the presence of heavy metals at more than permissible limits. Oral administration of waste water to the rats at the dose level of 26.6 ml kg,1 body wt. significantly reduced the weights of testes, epididymides and seminal vesicle. Treated animals showed a notable depression of various stages of spermatogenesis. The production of spermatids was inhibited by 70.8% in waste-water-treated rats. The populations of spermatogonia, preleptotene spermatocytes and secondary spermatocytes were decreased by 67.2, 71.1 and 73.2%, respectively. The total number of Sertoli cells was affected after waste water treatment. Reduced sperm count and motility resulted in treated groups. A significant fall in the content of various biochemical parameters of reproductive tissues was observed after water treatment. Copyright © 2003 John Wiley & Sons, Ltd. [source] The removal of reactive azo dyes by natural and modified zeolitesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2003B Arma Abstract The adsorption mechanism of three reactive dyes by zeolite has been examined with the aim of identifying the ability of zeolite to remove textile dyes from aqueous solutions. Towards this aim, a series of batch adsorption experiments was carried out, along with determination of the electrokinetic properties of both natural and modified zeolites. The adsorbent in this study is a clinoptilolite from the Gördes region of Turkey. The reactive dyes CI Reactive Black 5, Red 239 and Yellow 176 are typical azo dyes extensively used in textile dyeing. Adsorption tests were carried out as a function of mixing time, solids concentration, dye concentration and pH. The adsorption results indicate that the natural zeolite has a limited adsorption capacity for reactive dyes but is substantially improved upon modifying its surfaces with quaternary amines. An electrostatic adsorption mechanism involving the formation of a bilayer of amine molecules on the clinoptilolite surface onto which anionic dye molecules adsorb, depending on their polarities, is proposed. The results are also supported by electrokinetic measurements. The adsorption data were fitted to the Langmuir isotherm and it was found that the modified sepiolite yields adsorption capacities (qe) of 111, 89 and 61 mg g,1 for Red, Yellow and Black, respectively. These results are comparable to a popular adsorbent, activated carbon. Copyright © 2003 Society of Chemical Industry [source] THE TACTILE SENSORY EVALUATION OF KNITTED FABRICS: EFFECT OF SOME FINISHING TREATMENTSJOURNAL OF SENSORY STUDIES, Issue 2 2010SELSABIL EL-GHEZAL JEGUIRIM ABSTRACT Good textile sensory characteristics required by the consumers incites textile industrialists to improve the sensory properties of fabrics. Therefore, several textile finishing processes have been proposed to improve the feel of fabrics. This work investigates the effects of some finishing treatments on the tactile properties using sensory analysis. The studied finishing treatments, namely bleaching, dyeing in different conditions, bio-polishing, softening, emerizing and calendaring, were applied on 100% cotton knitted fabrics. The obtained sensory properties of treated fabrics are in accordance with each finishing treatment aim. Hence, the bio-polishing treatment confers to fabrics a less hairy feeling, softening procures to fabrics a more soft, hairy and elastic feeling and emerizing leads to a more hairy and soft feeling. PRACTICAL APPLICATIONS The practical use of the research presented in this paper is in the sensory evaluation of textile products. The tactile quality of fabrics is an important selling argument. Thus, the textile industrialists try to optimize the production, and especially finishing processes to improve the fabrics tactile feeling. Therefore, it seems necessary to develop tools describing and grading the sensory quality of the produced fabrics for similar consumers' evaluation. [source] Effect of ,-irradiation on the physical properties and dyeability of poly(vinyl butyral) blends with polystyrene and poly(ethylene glycol)POLYMER COMPOSITES, Issue 6 2008Horia M. Nizam El-Din Cast films of polymer blends essentially based on poly(vinyl butyral) (PVB) and equal ratios of polystyrene (PS) and poly(ethylene glycol) (PEG) were prepared from benzene and butyl alcohol solutions of the individual polymers. The effect of ,-irradiation on the thermal decomposition and tensile mechanical properties was investigated. Moreover, the effect of ,-irradiation on the dye affinity of PVB/PS and PVB/PEG for basic and acid dyestuffs was studied. The thermogravimetric analysis (TGA) study showed that the unirradiated PVB polymer films prepared in benzene displayed higher thermal stability than the same polymer films prepared in butanol. However, in all cases the thermal stability was found to increase with increasing ,-irradiation dose. On the other hand, PVB/PS blend possesses higher thermal stability than PVB/PEG, as shown from the determination of the weight loss (%) at different heating temperatures, the temperatures of the maximum rate of reaction and the activation energy. While, pure PS films showed the stress-strain behavior of brittle polymers, PVB/PS films showed the behavior of tough polymers with yielding properties. The results of dyeing clearly showed that the solvent type, blend composition, and irradiation dose are determining factors for the dye affinity for basic or acid dyes. For example, unirradiated PVB films prepared from butanol displayed a higher affinity for the basic and acid dyes than the same polymer prepared from the same benzene. However, PVB prepared from butanol showed higher affinity to the dyes than PS prepared from the same solvent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Effect of immobilization of polysaccharides on the biocompatibility of poly(butyleneadipate- co -terephthalate) filmsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2010Win-Chun Jao Abstract Aiming to improve the hydrophilicity, antibacterial activity, cytocompatibility, and hemocompatibility of poly(butyleneadipate- co -terephthalate) (PBAT) films, PBAT films were treated with ozone, grafted with chitosan (CS), and followed by covalent immobilization of either heparin (HEP) or hyaluronic acid (HA). The surface graft density of modified PBAT films was detected by X-ray photoelectron spectroscopy (XPS) and dyeing. The surface roughness of PBAT films was measured using an atomic force microscope (AFM). After immobilizing CS, PBAT films acquired antibacterial activity against Staphylococcus aureus and Escherichia coli. The adsorption of human serum albumin (HSA) and human plasma fibrinogen (HPF) on PBAT,CS,HEP and PBAT,CS,HA films was lower compared to that of native PBAT. Moreover, HEP immobilization could effectively reduce platelet adhesion and prolong the blood coagulation time, thereby improving the blood compatibility of PBAT. In addition, the growth of L929 fibroblasts was improved for HEP or HA immobilized PBAT, suggesting this surface modification was non-cytotoxic. Furthermore, PBAT,CS,HEP and PBAT,CS,HA exhibited higher cell proliferation than native PBAT. Copyright © 2009 John Wiley & Sons, Ltd. [source] Allergic contact dermatitis from temporary henna tattooTHE JOURNAL OF DERMATOLOGY, Issue 1 2009Dragan L. JOVANOVIC ABSTRACT Temporary henna tattooing has been very popular during recent years. Henna (Lawsonia inermis) is a plant from the Lythraceae family. For henna tattooing, henna dye is used. It is a dark green powder, made from the leaves of the plant, used for hair dyeing and body tattooing. Very often, para-phenylenediamine (PPD) is added to henna dye to make color blacker and to speed up dyeing. PPD may be a very potent contact sensitizer. We report a 9-year-old boy with allergic contact dermatitis due to temporary henna tattooing. Patch testing showed a positive reaction to PPD. After the treatment with topical corticosteroid and oral antihistamines, the lesion cleared with discrete residual hypopigmentation. [source] NADPH oxidase produces reactive oxygen species and maintains survival of rat astrocytesCELL BIOCHEMISTRY AND FUNCTION, Issue 2 2005Qing Liu Abstract Reactive oxygen species (ROS) produced by activated astrocytes have been considered to be involved in the pathogenesis of neurodegenerative diseases, while NADPH oxidase is an essential enzyme involved in ROS-mediated signal transduction. The goal of the present study was to determine whether NADPH oxidase plays a role in ROS generation and cell survival in rat astrocytes. We found that the release of ROS in rat astrocytes was significantly increased by stimulation with calcium ionophore or opsonized zymosan, which are known to trigger a respiration burst in phagocytes by the NADPH oxidase pathway. Further study indicated that diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, significantly suppressed the increase of ROS release caused by the calcium ionophore or opsonized zymosan. Cell survival assay and fluorescence double dyeing with acridine orange and ethidium bromide showed that DPI dose- and time-dependently decreased the viability of normal astrocytes, whereas exogenous supplementation of H2O2 can reverse the survival of DPI-treated astrocytes. For the first time, our results suggest that NADPH oxidase is an important enzyme for the generation of ROS in astrocytes, and the ROS generated by NADPH oxidase play an essential role in astrocyte survival. Copyright © 2004 John Wiley & Sons, Ltd. [source] Novel anti-bacterial acid dyes derived from naphthalimide: synthesis, characterisation and evaluation of their technical properties on nylon 6COLORATION TECHNOLOGY, Issue 2 2010Zinat Mohammadkhodaei As an attempt to combine the dyeing and functional finishing steps into one process, two novel anti-bacterial monoazo acid dyes based on N -ester-1,8-naphthalimide were synthesised. To do this, 4-amino- N -ethyl glycinate-1,8-naphthalimide was prepared, diazotised and then coupled to thiosalicylic acid or salicylic acid to produce anti-bacterial dyes. The synthesised dyes were purified and then fully characterised using Fourier Transform,infrared spectrometry, proton nuclear magnetic resonance spectroscopy and melting point analysis. Dispersion of the dyes was prepared in water and applied to nylon 6 fabrics. The novel dyes offered good build-up properties on the substrate. The anti-bacterial efficacy of the synthesised dyes was assessed, with the dyes showing activity against both Gram-positive and Gram-negative bacteria. [source] Improvement in the dyeability of viscoseCOLORATION TECHNOLOGY, Issue 5 2009D P Chattopadhyay The effect of alkaline pretreatment with sodium hydroxide and sodium zincate on the dyeability of viscose has been studied. Both agents could enhance the dye accessibility to viscose, but sodium hydroxide was found to be more effective compared with sodium zincate. The maximum exhaustion of different reactive dyes was found with 7.5% w/v sodium hydroxide pretreated samples. Both the rate of dyeing and final dyebath exhaustion of viscose was significantly improved after such pretreatment. The pretreatment could also effectively replace the electrolyte requirement for some reactive dyes. The alkaline pretreatment also generated higher colour depth on the printed fabric. The change in surface morphology of the fibre as a result of sodium hydroxide treatment was examined through scanning electron microphotography. The weight loss as a result of this treatment was critically studied. 10% w/v sodium hydroxide was found to cause maximum loss in weight of the viscose fibre. [source] Effect of enzyme treatment and dyeing on the mechanical properties of linenCOLORATION TECHNOLOGY, Issue 5 2009C W Kan In this paper, different concentrations of cellulase enzyme were used for treating linen fabrics. The pretreated linen fabrics were dyed using a bifunctional reactive dye at various concentrations. The effect of enzyme treatment, together with the dyeing process on the low-stress mechanical properties of the linen fabric, was then investigated. The low-stress mechanical properties were assessed quantitatively, including the tensile, shearing, bending, compression and surface properties of the enzyme-treated and dyed linen fabrics. The results revealed that the enzyme treatment with subsequent dyeing could alter these properties to a greater extent, depending predominantly on the concentration of enzyme used. [source] Adsorption behaviour of azo disperse dyes on polyurethane fibreCOLORATION TECHNOLOGY, Issue 3 2009Hong-Fei Qian Adsorption isotherms of disperse dyes were measured and the surfaces of dyed polyurethane, cellulose diacetate and polylactic acid fibres were observed using a scanning electron microscope and compared. Obvious crystal growth of the dyes occurred on the surface of the polyurethane fibres. The maximum dye uptake on polyurethane fibres and the degree of crystal growth varied greatly with the dye type. Factors such as the dye affinity for the fibre, crystallisation properties and dye solubility in the dyebath affect the sorbed state of the dye on the fibre surface. A mechanism is proposed for crystal formation on the fibre surface during dyeing of polyurethane fibre with disperse dyes. [source] One-bath union dyeing of wool/polytrimethylene terephthalate blends,COLORATION TECHNOLOGY, Issue 4 2008Jinhuan Zheng The one-bath dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool has been investigated. The exhaustion of selected Terasil disperse dyes on PTT fibre and Lanasol reactive dyes on wool was measured as a function of temperature, together with the cross-staining of the Terasil dyes on the wool component and the Lanasol dyes on PTT component. Most Terasil disperse dyes achieved satisfactory dye uptake on PTT at 110 °C, whereas on conventional polyester (polyethylene terephthalate) temperatures of up to 130 °C are required. An optimised union-dyeing technique for wool/PTT blends was developed which minimised the staining of Terasil disperse dyes on wool and produced dyed goods with high levels of wet colour fastness. Carriers were not required to enhance the dyeability of PTT at low temperatures. The wool component appeared to be protected against damage at 110 °C by the reactive dyes. The results indicate the potential for blending PTT fibre and wool to produce fabrics that are easier to dye at lower temperatures than conventional wool/polyester blends. [source] Effects of a cationic diblock copolymer derived from [2-(methacryloyloxy)-ethyl]trimethylammonium chloride in the dyeing of cotton with reactive dyeCOLORATION TECHNOLOGY, Issue 4 2008Shin Young Han A cationic diblock copolymer (PEO45 -MeDMA) derived from [2-(methacryloyloxy)-ethyl]trimethylammonium chloride (MeDMA) gave a positive charge to a cotton surface and provided strong attraction to an anionically charged reactive dye. PEO45 -MeDMA was used as the cotton pretreatment. The dyeability of cationised cotton fabrics using CI Reactive Blue 250 was found to be dependent on the PEO45 -MeDMA concentration. The colour strength and fastness properties of the dyed fabrics using the PEO45 -MeDMA copolymer and sodium sulphate were compared. The dyeability of the cotton fabrics pretreated with PEO45 -MeDMA indicated higher dye uptake than that of sodium sulphate. This suggests that the pretreatment of cotton by PEO45 -MeDMA diblock copolymer can be considered as an alternative to the use of the exhausting agent sodium sulphate. [source] Determining the dependence of colour values on yarn structureCOLORATION TECHNOLOGY, Issue 3 2008Mehmet Ozturk The colour values of knitted cotton fabrics made from single and plied ring and compact yarns were investigated before and after dyeing. The fabric samples were knitted under the same constructional properties and then dyed with direct and reactive dyes. It was found that fabrics with ring yarns had high lightness and low chroma and colour strength values compared with fabrics with compact yarns. Also colour strength and colour difference values of dyed fabrics were assessed after increasing abrasion cycles (2500, 5000, 7500 and 10 000). The main changes in colour strength values were observed at 2500 abrasion cycles. The effect of abrasion on colour difference values of fabrics having ring yarns was more obvious than fabrics having compact yarns. [source] Simultaneous afterclearing and decolorisation by ozonation after disperse dyeing of polyesterCOLORATION TECHNOLOGY, Issue 4 2007Hüseyin Aksel Eren A set of trials have been conducted to examine the efficiency of ozonation on afterclearing of disperse dyed poly(ethylene terephthalate) fibres. Ozonation was performed in the cooled dyebath after the completion of the dyeing cycle. The ozone concentration used was 12.8 ± 0.3 mg/min at a gas flow rate of 400 ml/min. The results indicate that 3 min ozonation time is appropriate to achieve wash fastness results comparable to conventional reduction clearing. These results were obtained with simultaneous dyebath decolorisation ratios up to 67% and without significant colour yield (K/S value) losses of the dyed fabric. Ozonation periods exceeding 3 min caused significant colour yield (K/S value) losses, although dyebath decolorisation ratios increased up to 82% and wash fastness properties further improved. The chemical oxygen demand of the dyeing process decreased up to 62% by the ozonation afterclearing. The advantages of the ozonation afterclearing process are savings in terms of water, energy and time and reduction in environmental load. [source] Review of the process development aspects of electrochemical dyeing: its impact and commercial applicationsCOLORATION TECHNOLOGY, Issue 3 2007M Anbu Kulandainathan This review discusses the recent progress made in both direct and indirect electrochemical dyeing processes and the parameters that control the dyeing process. [source] Dyeing poly(lactic acid) fibres in supercritical carbon dioxideCOLORATION TECHNOLOGY, Issue 5 2006Elke Bach A study has been conducted into the dyeing of poly(lactic acid) fibres in supercritical carbon dioxide. The fibres were completely dyed using disperse dyes at 50 °C as shown by fibre cross-sections, although high colour depths in dark shades still prove challenging. Dye uptake increased significantly at temperatures ,80 °C. At 95 °C in supercritical carbon dioxide, shrinkage and hardening of raw poly(lactic acid) were observed which could partly be overcome by the supercritical carbon dioxide extraction step. Afterclearing with cold supercritical carbon dioxide (to remove unfixed dye after dyeing) decreased the colour depth and led to non-uniform dyeing results on poly(lactic acid). Wash and rub fastness was good to very good also when poly(lactic acid) was not aftercleared in supercritical carbon dioxide. Fibre damage and elongation at break in supercritical carbon dioxide were similar to water. [source] | |||||||||||||||||||