Science Journals RSS Feeds
Sponsored Links
Recent Comments

    Dyes and Pigments

    Synthesis and application of KM‐type reactive dyes containing 2‐ethoxy‐4‐chloro‐s‐triazine

    Abstract

    A new kind of hetero‐bifunctional reactive dye containing 2‐ethoxy‐4‐chloro‐s‐triazine, with better activity matching with β‐hydroxyethyl sulphone sulphate at a low fixation temperature, was successfully synthesised and characterised. An ethoxy group was designed to be introduced into triazine to increase the substantivity and the reactivity of the dyes. Thereby, the fixation of mono‐s‐chlorotriazine/hydroxyethyl sulphone sulphate (KM‐type) bifunctional reactive dyes on cotton was improved, and dyeing under mild conditions with high fixation was realised. Nineteen dyes with orange, red and blue colours were synthesised and characterised by UV‐Vis and infrared spectroscopy and mass spectrometry. Synthesised dyes were dyed at 60, 75 and 90°C, respectively. Exhaustion and reactivity for all of the ethoxy‐containing KM‐type dyes was over 90% at the optimal temperature, and fixation was over 87%, which was higher than the ethoxy‐free comparative dyes. The optimal fixation temperature of ethoxy‐containing dyes was initially reduced to 75°C, and then to 60°C. Compared with comparative dyes, the wash fastness and light fastness were basically unchanged, and the wet rub fastness of the H‐acid series was reduced by one grade.

    …read more

    Source:: Coloration Technology

          

    Poly(methyl methacrylate)/polysiloxane core‐shell latex as a deepening agent for dyed polyester fabric

    Abstract

    Polyester fabrics are usually difficult to dye deeply due to their high refractive indexes. In this study, poly(methyl methacrylate)/polysiloxane core‐shell latex was used as a deepening agent in the colour‐deepening finishing of dyed polyester fabrics by lowering the refraction index and enhancing the diffuse reflection via the rough surface. Poly(methyl methacrylate)/polysiloxane core‐shell latex has a better shade‐deepening effect than polysiloxane latex on dyed polyester fabrics. The mass ratio of core/shell monomer and the finishing conditions of the polyester fabrics had a large influence on shade deepening. The optimum finishing conditions were obtained for a mass ratio of core/shell monomer of 1:2, a deepening agent concentration of 10 wt%, a pick‐up of 80%, and a curing temperature of 180°C. After a deepening finishing, the dyed polyester fabrics showed a small colour difference and the colour fastness barely decreased.

    …read more

    Source:: Coloration Technology

          

    Aryl and heteroaryl azo dyes derived from 6, 8‐dichloro‐4‐hydroxyquinolin‐2 (1H)‐one: synthesis, characterisation, solvatochromism and spectroscopic properties

    Abstract

    In this research study, 6, 8‐dichloro‐4‐hydroxyquinolin‐2(1H)‐one was prepared by the thermal cyclocondensation of 2‐(2, 4‐dichlorophenylcarbamoyl) acetic acid or N, Nʹ‐bis(2,4‐dichlorophenyl)malonamide at 140‐150°C in polyphosphoric acid, resulting in a yield of 48%. This compound was then coupled with a series of diazonium salts derived from aromatic and heteroaromatic amines for synthesis of the corresponding azo dyes. The structures of the compounds were confirmed using elemental analysis as well as ultraviolet‐visible, Fourier Transform‐infrared and proton nuclear magnetic resonance spectroscopy. The effects of organic solvents with different polarities, pH values and substituents of the diazotising components on the maximum absorption wavelength of the colorants were discussed and evaluated in detail. The acidity constants (pK
    a) of the dyes were also determined using the spectrophotometric method in an ethanol‐water mixture (80:20, v/v) at 20‐23°C.

    …read more

    Source:: Coloration Technology

          

    Preparation of carboxylated graphene oxide nanosheets/polysulphone hollow fibre separation membranes with improved separation and dye adsorption properties

    Abstract

    Novel hollow fibre polysulphone (PSF) separation membranes were prepared via the incorporation of carboxylated graphene oxide (cGO) in membrane matrix during the dry‐wet spinning process to improve the membrane performance of water flux and dye adsorption. The surface composition and morphology of the prepared cGO‐incorporated hollow fibre membranes were characterised by means of Fourier Transform–infrared spectra and scanning electron microscopy. The effects of different cGO contents on membrane surface hydrophilicity, separation performance, anti‐compaction and adsorption properties were investigated through measurements of the water contact angle, cross‐flow filtration and methylene blue (MB) adsorption experiments. The results demonstrated that the cGO‐incorporated membranes had more hydrophilic surfaces, higher permeation flux, better anti‐compaction properties and a higher adsorption rate of MB than that of the PSF control membrane. When cGO content was 0.45 wt.%, the pure water flux of the modified membrane increased from 90.56 to 148.26 l m−2 h−1 at 0.1 MPa; also, rejections of bovine serum albumin and polyethylene glycol (PEG‐20000) maintained relatively high values of 98.81 and 93.89%, respectively. The incorporation of cGO nanosheets could effectively improve membrane anti‐compaction properties and the adsorption rate of MB.

    …read more

    Source:: Coloration Technology

          

    Light stability in cyan and magenta tones using standard and highly chromatic toner particles

    Abstract

    An increasing requisite regarding the reproduction quality of electrophotographic printing machines demands improvement of new electrophotographic toner formulation, especially used pigments. The subject of this paper is a comparison of prints realised by depositing high chroma (HC) and standard emulsion aggregation (EA) toner on gloss fine art paper. HC toner has a different composition of the cyan and magenta tones compared with the corresponding standard EA toner tones and therefore behaves differently under real conditions. The patches used for this experiment were cyan and magenta tone prints with tone values (TVs) of 0, 20, 60 and 100%. Ultraviolet (UV) degradation was measured over time intervals of 0, 6, 12, 24, 48, 96, 144 and 240 h for all patches. Results (laboratory values) were calculated using colorimetric difference. Values were plotted as a function of time in tonal degradation graphs. A model was created using non‐linear regression‐based modelling. The experiment demonstrates that magenta patches are more susceptible to degradation in comparison with cyan patches. With the increase in tonal value, it is noticeable that the colorimetric difference is higher. Colorimetric differences calculated using HC magenta toner and standard EA cyan toner (100% TV) were higher than ∆E = 5, starting to appear after 6 h of exposure to UV radiance. After 12 h of exposure, colorimetric differences of standard magenta tones that were greater than ∆E = 5 also started to appear. Cyan patches (100% TV) printed with HC toner were more stable than the other patches, and after 240 h of exposure had not crossed the boundary of ∆E = 5.

    …read more

    Source:: Coloration Technology

          

    Light stability in cyan and magenta tones using standard and highly chromatic toner particles

    Abstract

    An increasing requisite regarding the reproduction quality of electrophotographic printing machines demands improvement of new electrophotographic toner formulation, especially used pigments. The subject of this paper is a comparison of prints realised by depositing high chroma (HC) and standard emulsion aggregation (EA) toner on gloss fine art paper. HC toner has a different composition of the cyan and magenta tones compared with the corresponding standard EA toner tones and therefore behaves differently under real conditions. The patches used for this experiment were cyan and magenta tone prints with tone values (TVs) of 0, 20, 60 and 100%. Ultraviolet (UV) degradation was measured over time intervals of 0, 6, 12, 24, 48, 96, 144 and 240 h for all patches. Results (laboratory values) were calculated using colorimetric difference. Values were plotted as a function of time in tonal degradation graphs. A model was created using non‐linear regression‐based modelling. The experiment demonstrates that magenta patches are more susceptible to degradation in comparison with cyan patches. With the increase in tonal value, it is noticeable that the colorimetric difference is higher. Colorimetric differences calculated using HC magenta toner and standard EA cyan toner (100% TV) were higher than ∆E = 5, starting to appear after 6 h of exposure to UV radiance. After 12 h of exposure, colorimetric differences of standard magenta tones that were greater than ∆E = 5 also started to appear. Cyan patches (100% TV) printed with HC toner were more stable than the other patches, and after 240 h of exposure had not crossed the boundary of ∆E = 5.

    …read more

    Source:: Coloration Technology

          

    Colour recipe prediction using ant colony algorithm: principle of resolution and analysis of performances

    Abstract

    This paper presents a new method for colour recipe prediction using ant colony optimisation. Three reactive dyes, namely CI Reactive Yellow 145, CI Reactive Red 238 and CI Reactive Blue 235, were used for colour formulation. Samples of 100% cotton fabrics were used for dyeing. The objective was to assure, control and optimise the colour formulation step by determining the dyes to be applied and their respective concentrations to reproduce the desired shades. The criterion of optimisation is to minimise the colour differences [Colour Measurement Committee (2:1)] between the target colour and the colour obtained by the proposed recipe. Errors between the proposed recipe and actual concentrations are also evaluated. The developed algorithm showed good performances with small colour differences between the target and reproduced colours (all lower than 0.7).

    …read more

    Source:: Coloration Technology

          

    Colour recipe prediction using ant colony algorithm: principle of resolution and analysis of performances

    Abstract

    This paper presents a new method for colour recipe prediction using ant colony optimisation. Three reactive dyes, namely CI Reactive Yellow 145, CI Reactive Red 238 and CI Reactive Blue 235, were used for colour formulation. Samples of 100% cotton fabrics were used for dyeing. The objective was to assure, control and optimise the colour formulation step by determining the dyes to be applied and their respective concentrations to reproduce the desired shades. The criterion of optimisation is to minimise the colour differences [Colour Measurement Committee (2:1)] between the target colour and the colour obtained by the proposed recipe. Errors between the proposed recipe and actual concentrations are also evaluated. The developed algorithm showed good performances with small colour differences between the target and reproduced colours (all lower than 0.7).

    …read more

    Source:: Coloration Technology

          

    Analysis of keratin films as screening tools for predicting the efficacy of potential hair dyes

    Abstract

    The technology for generating high quality keratin films has recently advanced and led to their implementation in a variety of applications. As an initial step toward investigating the films as a screening tool for predicting the efficacy of potential hair dyes, CI Acid Orange 7 was applied to a set of opaque and translucent films. Overlaid time‐of‐flight secondary ion mass spectrometry images arising from protein and dye fragments revealed that dye uniformly penetrated both film types. Results also showed that the relative concentration of dye in each film complemented outcomes from ultraviolet‐visible analysis and revealed that the translucent film contained a higher dye concentration. Scanning electron microscopy analysis of film morphology suggested that the observed difference was due to the higher porosity of the opaque film, which facilitated dye desorption during the rinsing step. Consequently, the translucent film was judged to be a better substrate for screening potential new hair dyes.

    …read more

    Source:: Coloration Technology

          

    Sponsored Links
    Archives

    Copyright © 2013. All Rights Reserved.