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    Dyes and Pigments

    Over the past few years, although many studies have investigated colour harmony, most of those used the planar colour configuration, which is not in line with the design requirements of real‐life products. Therefore, this study used 11 basic colours and five types of colour scheme techniques to derive 141 colour combinations applied upon a physical 3D colour configuration to observe the phenomena of colour harmony. The results show that colour harmony on a 3D colour configuration is different from that on a planar colour configuration, and can be divided into four phenomena: (i) lightness difference was found to determine the colour harmony while achromatic colour was configured with achromatic colour; (ii) lightness sum prompted colour harmony while chromatic colour was configured with achromatic colour; (iii) lightness sum and chroma sum were found to determine colour harmony while chromatic colour was configured with chromatic colour with a two‐colour hue angle difference >90°; and (iv) lightness sum and hue difference were a determination of colour harmony while chromatic colour was configured with chromatic colour with a two‐colour hue angle difference of ≤90°. On the basis of these phenomena, this study develops a colour harmony model based on the colour parameters, most of which are derived from the addition of the colour attributes of two colours. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    Oxidised aluminum coatings are useful in various high technology applications to protect surfaces from negative environmental effects. In this study, aluminum discs and foils of industrial alloys were anodised in a sulphuric acid/oxalic acid electrolyte. Scanning electron microscopy was used to determine the pore diameter, distribution and surface porosity. The anodising procedure was adapted to produce near‐hollow templates on aluminium foil, onto which aqueous solutions of commercial chromium‐complexed anionic azodyes were dropped. Raman spectroscopy was used to detect the penetration of dye compounds based on the most intensive vibrational modes. Each dye was successfully monitored to assess its penetration rate and behaviour in the anodised coating. This method could be applied to characterise newly developed organic dyes for aluminum colouring. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    The effect of pigment colours, cyan (C), magenta (M) and yellow (Y), and a blend of these (CMY blend) on the printing performance of synthetic leather using a ultraviolet (UV)‐curable water‐borne polyurethane acrylate binder and two types of photoinitiators was investigated. The curing process was carried out at different radiation doses using gallium and mercury UV lamps in combination. The performance of the prints was evaluated with abrasion resistance, crock fastness, gloss and hardness values and K/S. Chemical changes in the cured film structures due to UV curing were analysed by Fourier Transform–infrared spectroscopy measurements. The highest hardness values for clear and pigmented cured films were obtained with a gallium and mercury lamp combination at the highest energy density (1529 mJ/cm2). The highest K/S was obtained for the sample printed with the formulation including the C pigment and cured under a gallium and mercury lamp combination at low energy density (398 mJ/cm2). The M‐pigmented film displayed the highest hardness and abrasion resistance, whereas lower values were obtained with films pigmented with Y and C, and CMY blend, successively. The highest dry and wet crock values were obtained with the formulation including the M pigment. CMY‐pigmented film showed the highest gloss values at all energy densities. The pigment colour affected the curing degree of printed films due to the different absorption/transmission intervals of each colour in the UV spectrum. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    The series of rigid meso‐aminophenyl‐substituted heptamethine dyes presented herein exhibit surprising fluorescence properties, demonstrating larger Stokes shifts when compared with both structurally similar rigid meso‐chlorophenyl and linear heptamethine dyes. Based on their photophysical properties, these are of considerable importance to the development of contrast agents, within biology and medicine. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    Microbial dyes have received substantial attention because of their natural environmental protection, simple access, and reduced regional and seasonal restriction. In this work, a microbial dye, the yellow pigment produced by Metarhizium anisopliae, was first studied then applied. The strain produced by the culture was identified, and the conditions for producing yellow pigment were optimised. Further, the stability of M. anisopliae yellow pigment was examined, and the pigment was applied to the dyeing of silk and wool fabrics. The results showed that the homology of the strain with M. anisopliae was 99.98%. In liquid fermentation culture, the optimal carbon source was glucose, and the dosage was 30 g/l. The maximum pigment yield can be obtained by culturing with 4% v/v of inoculation quantity at pH 7 and 30 °C. In addition, the effects of pH, temperature and metal ions on the yellow pigment of M. anisopliae were significant. The optimum dyeing process conditions were dyeing temperatures of 80 °C for silk and 90 °C for wool, with a dyeing time of 60 min. This research developed a novel microbial dye and studied its application for the dyeing of protein fibres. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    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. [...]
    Fri, Jul 19, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    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. [...]
    Thu, Jul 11, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    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. [...]
    Thu, Jul 11, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
    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. [...]
    Wed, Jul 10, 2019
    Source: Coloration Technology Category: DYES PIGMENTS
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