Improvement of polyester dyeing at low temperature

• Autores: Shahram Radei
• Directores de la Tesis: José M. Canal Arias (dir. tes.), Mònica Ardanuy Raso (codir. tes.)
• Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2020
• Idioma: español
• Programa de doctorado: Programa de Doctorado en Ingeniería Textil y Papelera por la Universidad Politécnica de Catalunya
• Calificación: Sobresaliente Cum Laude
• Materias:
  • Ciencias tecnológicas
    • Tecnología textil
      • Fibras sintéticas
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• Resumen

  • In this thesis the polyester dyeing at low temperatures has been assessed with two different methods: exhaustion method and thermosol method. Exhaustion dyeing process was performed with high and low molecular-weight disperse dyes in presence of small proportion of two non-toxic and biobased aromatic auxiliaries, namely o-vanillin and coumarin with an organic co-solvent (n-butylacetate) in a micro-emulsion system. The kinetic and thermodynamic parameters of this process were analysed. The values of entropy and activation diffusion coefficients were obtained from the theory of absolute rates of dyeing. Moreover, color fastness to washing and ironing were determined. The study proved that color strength and dyestuff absorption on the polyester with this new micro-emulsion formulation at low temperature (95ºC) are similar to those achieved with high temperature exhaustion system at 135 ºC. Moreover, this new micro-emulsion system has the advantage of using eco-friendly auxiliaries being the dyeing system favorable from both economic and environmental points of view. Comparing both auxiliaries, it was found that, in general, polyester samples dyed with o-vanillin/n-butylacetate system yielded higher colour strength (K/S) and exhaustion percentage than the ones dyed with coumarin/n-butylacetate. Higher activated energies, activated entropy and diffusion coefficient were found for polyester samples dyed with o-vanillin/n-butylacetate. Thermosol process was carried out with a low molecular disperse dye using two different impregnation padding baths (with or without lecithin) at two different impregnation times at 20º C (one minute or twenty four hours). The study demonstrated that values of K/S, dyeing efficiency, and dyestuff concentration into the fiber (mg dye/ g fiber) of dyed polyester samples increased due to action of lecithin. This reveals that if the padding solution contains lecithin less quantity of dyestuff will be required to reach same color shade. Moreover, samples dyed with twenty four hours of impregnation lead to higher color strength, efficiency and dyestuff concentration in the fiber than thermosolated polyester samples treated during one minute of impregnation time.