Lime-free unhairing : Part 5. Some peculiarities of dyeing lime-free leather / A. Zaliauskiene in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 90, N° 2 (03-04/2006)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 90, N° 2 (03-04/2006) . - p. 73-79 Titre : Lime-free unhairing : Part 5. Some peculiarities of dyeing lime-free leather Type de document : texte imprimé Auteurs : A. Zaliauskiene, Auteur ; Kestutis Beleska, Auteur ; Virgilijus Valeika, Auteur ; J. Balciuniene, Auteur ; V. Valeikene, Auteur ; V. Tricys, Auteur Année de publication : 2006 Article en page(s) : p. 73-79 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Coefficient de diffusion Un coefficient de diffusion est une grandeur caractéristique du phénomène de diffusion de la matière. Le coefficient de diffusion mesure le rapport entre le flux molaire dû à la diffusion moléculaire, et le gradient de concentration de l'espèce chimique considérée (ou, plus généralement, de la variable d'effort entraînant cette diffusion), comme formulé par la loi de Fick. Colorants Cuirs et peaux -- Teinture Hydrophobie Pénétration (physique) Rouge (couleur) Thermodynamique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The interaction of leather, prepared by the lime-free method, and a series of 1:2 metal complex dyes has been investigated by determining the distribution of the dyes at equilibrium. Kinetic and thermodynamic aspects such as the rate of dyeing, heat of dyeing, entropy, affinity of dyes on the lime-free and conventional leather have been studied. The diffusion coefficient was calculated by means of the Weisz pore and Krenk models. It has been established that the sorption isotherms for these dyes on both types of leather fibres show a Langmuir type of behaviour. The dyeing system hydrophobic C.I. Acid Red 247/lime-free leather has a positive heat of dyeing: dyeing is an endothermic process in this case. The change of entropy of interaction of hydrophobic C.I. Acid Red 247 and leather fibres is 24 cal/mol•K. An increased degree of freedom should be associated with water molecules such as those hydrating the dye and the fibre, and possibly, due to randomness in the fibre itself. This decreased degree of the order of water molecules results in a positive change of entropy, which then is the thermodynamic cause of the hydrophobic bonding. The influence of factors such as, initial amount of dye, pH of leather and temperature on the dyeing process was established. The results have shown that lime-free leather absorbs lesser amounts of dye during dyeing but that, the dye penetrates more deeply compared with conventional leather. The amount of dye, pH and temperature has no influence on such a tendency. On the other hand, the investigation has shown that the factors mentioned have a more marked influence on the progress of dyeing of lime-free leather compared with dyeing conventional leather. This means that inconsiderable deviation from determined parameters of dyeing can markedly deteriorate the quality of the dyed leather. The data obtained have confirmed that the change in the method of liming considerably influences subsequent processes in leather processing. Note de contenu : - EXPERIMENTAL PROCEDURE : Leather samples for dyeing - The preparation of leather fibres for dyeing - Dyes and dyeing - Determination of hydrophobicity of dyes - Determination of depth of dye penetration into leather - Investigation of dyeing kinetics - Thermodynamic investigation of dyeing - RESULTS AND DISCUSSION : Kinetic and thermodynamic investigation - Investigation of dyeing parameters on the progress of dyeing - Table 1 : Indexes of pelt and leather obtained by use of lime-free and conventional unhairing - Table 2 : The dependence of diffusion coeffficient on unhairing method - Table 3 : The thermodynamic characteristic of dyeing process En ligne : https://drive.google.com/file/d/16mWq3L-c0sNpayWDNSSXPgzVTvU4htbU/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39160 [article]

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