Thermodynamics of leather dyeing : III. The preparation of chrome-tanned hide powders and their interaction with C.I. Acid Orange 7 / A. T. Atto in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS, Vol. 55, N° 3 (03/1971)

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS > Vol. 55, N° 3 (03/1971) . - p. 84-103 Titre : Thermodynamics of leather dyeing : III. The preparation of chrome-tanned hide powders and their interaction with C.I. Acid Orange 7 Type de document : texte imprimé Auteurs : A. T. Atto, Auteur ; H. E. Nursten, Auteur Année de publication : 1971 Article en page(s) : p. 84-103 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Colorants acides Cuirs et peaux -- Teinture Entropie (thermodynamique) Orange (couleur) Poudre de peaux Tannage au chrome Thermodynamique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A procedure has been developed for chrome-tanning hide powder and it has been used to prepare a range of chrome-tanned hide powders with increasing chrome contents. The interaction of these tanned hide powders with the pure dye acid of C.I. Acid Orange 7 has been studied thermo-dynamically. The saturation capacity of the tanned hide powder for the acid dye increases almost linearly with the amount of chromium present, a chrome oxide content of about 3 % leading to a saturation capacity about twice that of untanned hide powder. The saturation capacities can be sur¬prisingly large, rising to almost three molecules dye bound per chromium atom. Chrome-tanned hide powder has been found to have a lower affinity for the acid dye than untanned, which is connected with the much larger satura¬tion capacity and the consequently lower activity in the fibre produced by a given amount of dye on the hide powder. The affinity at 60°c is independent of minor differences in tannage, but decreases with increasing amounts of chromium. The affinity increases with temperature in the range 25-75°c, while the saturation capacity decreases. Ageing chrome-tanned hide powder does not affect the affinity, but decreases somewhat the saturation capacity. Dyeing chrome-tanned hide powder appears to be exothermic and the entropies of dyeing are positive, the process thus being thermodynamically similar to dyeing untanned hide powder. Note de contenu : - Preparation of a number of batches of chrome-tanned hide powder (A) C20 hide powder - (B) ATA hide powder, Batch 1 - (C) ATA Hide powder, Batch 2 - (D) ATA hide powder (relatively very low chrome content) batch 3a - (E) ATA hide powder (relatively High chrome content), Batch 3b - Analysis of the tanned hide powders - Purification and analysis of the dye used - Dyeing - Reversibility of dyeing - Table 1 : Analysis of the tanned hide powders - Table 2 : Experimental data and quantities calculated therefrom - Table 3 : Saturation capacities of some chrome-tanned hide powders for C.I. Acid Orange 7 - Table 4 : Affinity of C.I. Acid Orange 7 for some chrome-tanned hide powders - Table 5 : Variation of affinity of C.I. Acid Orange 7 for chrome-tanned hide powder with chrome content - Table 6 : Comparison of the activity of C.I. Acid Orange 7 in tanned and untanned hide powder - Table 7 : Heats and entropies of dyeing of some chrome-tanned hide powders with C.I. Acid Orange 7 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35668 [article]

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Thermodynamics of leather dyeing / A. T. Atto in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS, Vol. 55, N° 5 (05/1971)

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS > Vol. 55, N° 5 (05/1971) . - p. 163-174 Titre : Thermodynamics of leather dyeing : IV. Dyeing of chrome-tanned hide powder with simple acid dyes Type de document : texte imprimé Auteurs : A. T. Atto, Auteur ; H. E. Nursten, Auteur Année de publication : 1971 Article en page(s) : p. 163-174 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Colorants acides Cuirs et peaux -- Teinture Entropie (thermodynamique) Poudre de peaux Tannage au chrome Titrage thermométrique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The previous study of the interaction between chrome-tanned hide powder and C.I. Acid Orange 7 has been extended to seven other simple acid dyes in the form of their specially purified dye acids. Good reciprocal plots were obtained at 45 and 60°c, leading to saturation capacities greater than 2 meq/g dry hide substance, except for the dye acids bearing sulphonic groups peri to the azo link. The affinities obtained are lower than those for untanned hide powder and this must be viewed as a consequence of the much greater saturation capacity, which leads to the production of a lower activity in the fibre by a given amount of dye. The affinity of a dye acid for chrome-tanned hide powder increases with the insertion of a methyl group or a fused-on benzene ring, but movement of a sulphonic group to a position peri to the azo link reduces it. Overall, the standard heats and entropies of dyeing chrome-tanned hide powder are of the same sign and order of magnitude as those for the untanned substrate. The thermodynamics of dyeing chrome-tanned hide powder thus do not appear to differ fundamentally from those of dyeing untanned hide powder. Note de contenu : - EXPERIMENTAL : The dyes - Substrates - Dyeing - RESULTS AND DISCUSSION : The reciprocal plot - Titration curves - Saturation capacities - Affinities - Heats of dyeing - Entropies of dyeing - Table 1 : Experimental data and quantities calculated therefrom - Table 2 : Saturation capacities, affinities and ratio dye acid/Cr atom of chrome-tanned ATA 1114e powder for a range of simple dye acids - Table 3 : Affinities of some simple dye acids for untanned and tanned hide powder kcal/mole - Table 4 : Heats and entropies of dyeing chrome-tanned hide powder with some simple dye acids at 45-60 °C Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35667 [article]

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