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Study of a chrome tanning process without float and with low-salt content compared to a traditional process. Part I / Josep Maria Morera in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 7 (07/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 7 (07/2006) . - p. 254-259 Titre : Study of a chrome tanning process without float and with low-salt content compared to a traditional process. Part I Type de document : texte imprimé Auteurs : Josep Maria Morera, Auteur ; Heinz-Peter Germann, Auteur ; J. Costa, Auteur ; Lluis Ollé, Auteur ; Anna Bacardit, Auteur Année de publication : 2006 Article en page(s) : p. 254-259 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The traditional chrome-tanning process poses several disadvantages from the environmental point of view including effluent volume as well as chromium and chloride content. We have thus modified the process in order to minimize these disadvantages. The tanning process has been carried out with almost no float by simply utilizing the float already contained in the hide. As there is very little water, the quantity of sodium chloride required to avoid the swelling of the skin decreases sharply, due to the acidic conditions. In a corresponding manner, the mechanical work on the skin increases and the fixation of chrome salt is greater. Water consumption and chrome discharge are dramatically lower using the new system instead of the traditional system. A comparison of results shows that by using the new system water consumption decreases by 78 percent, chrome oxide content by 86 percent and chlorides present in the effluents by 94 percent. En ligne : https://drive.google.com/file/d/1xXjaqE-Av6mh2QsIhitmdVKeo_WTv8Tg/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3994 [article]

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The composition analysis of organic acid masked aluminium tannig solutions by ferron assay and GFC / Keyi Ding in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 7 (07/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 7 (07/2006) . - p. 260-265 Titre : The composition analysis of organic acid masked aluminium tannig solutions by ferron assay and GFC Type de document : texte imprimé Auteurs : Keyi Ding, Auteur ; Jun Liu, Auteur ; Tingyou Zhang, Auteur Année de publication : 2006 Article en page(s) : p. 260-265 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Earlier theoretical assumptions were that, in tanning solutions, aluminum formed linear polymeric complexes similar to chromium with a maximum of four Al3+ nuclei in a complex. In this paper, the sizes of aluminum complexes, composition distribution and coordination of organic acid anions with Al3+ nuclei were determined by ferron assay, gel filtration chromatography (GFC) and low-pressure ion chromatography (LPIC). The results were as follows: (1) In the pH range of aluminum tanning process (pH=2.5-5.0), two types of organic acid masked aluminum complexes were found: Ala, mononuclear complexes, and Alb, polymeric complexes (small polymeric complexes containing 2-4 Al3+ nuclei, as well as larger "Al13 like" complexes). The percentage of Alb increased dramatically when pH was increased from 3.0 to 4.0, with more than 80% of the total Al3+ in this state at pH ≥3.5. (2) In organic acid masked aluminum salt solutions, most of the added organic acid anions were in "free" state, i.e., they were not coordinated with Al3+ nuclei. (3) In solutions of citrate masked aluminum sulfate, whatever the dose of citrate, the first elution fractions had unusually large values of [Al3+]/[Cit], some greater than 30. These results suggest that there might be something about the structure of aluminum complexes in tanning solutions that earlier theoretical assumptions did not consider. The results of this paper may provide some theoretical and practical guidance for a better understanding of the mechanism of aluminum tanning or aluminum combination tanning with other tannins. En ligne : https://drive.google.com/file/d/1wPo2jvvOOl9S4hrvhOJsPRrNE6ALYfAG/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3995 [article]

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Azardirachta indica : A green material for curing of hides and skins in leather processing / Vasudevan Preethi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 7 (07/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 7 (07/2006) . - p. 266-273 Titre : Azardirachta indica : A green material for curing of hides and skins in leather processing Type de document : texte imprimé Auteurs : Vasudevan Preethi, Auteur ; Veerapan Rathinasamy, Auteur ; Chandra Babu Narasimhan Kannan, Auteur ; Praveen Kumar Sehgal, Auteur Année de publication : 2006 Article en page(s) : p. 266-273 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : TAMIL N Common salt (Sodium chloride) in solid form is extensively used in preservation of raw hides and skins. A large quantity of this material is discharged in the liquid effluent as Total Dissolved Solids (TDS) during soaking operation in leather processing. In Central Leather Research Institute (CLRI), Chennai, we have attempted to replace common salt with an herbal-based formulation prepared using Azardirachta indica (common Indian name - Neem) in preservation of raw goatskins. After successful trials in CLRI, the material has been successfully field tested at a rural location in India where large quantity of goatskins is collected by local people for trading. The physical, chemical and subjective assessment of wet blues and crust leathers from the skins prepared with this material compare favorably with salt preserved skins. Use of Azardirachta indica in preservation also offers considerable reduction of TDS in liquid tannery effluent and material after the usage can be scrapped off from the skins and composted to get garden manure, thereby offering a better solution for its disposal. En ligne : https://drive.google.com/file/d/1bxztT4KNjHQrcOZCVy7C4jqzYHeZ36Mz/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3996 [article]

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The effect of ultrasound on bovine hide collagen structure / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 7 (07/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 7 (07/2006) . - p. 274-283 Titre : The effect of ultrasound on bovine hide collagen structure Type de document : texte imprimé Auteurs : Eleanor M. Brown, Auteur ; Donna M. Stauffer, Auteur ; Peter H. Cooke, Auteur ; Gennaro J. Maffia, Auteur Année de publication : 2006 Article en page(s) : p. 274-283 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Applications of ultrasound in leather processing have been researched for more than 50 years. Although these studies showed that ultrasound could have beneficial effects on hide preparation, tanning and finishing processes, the costs associated with the development of a new technology outweighed the benefits. Ultrasound is now a mature science, used to improve the efficiency of processes for the manufacture of a variety of materials. It may well offer a path toward the use of fewer (less) chemicals in the production of quality leather. However, the effects of ultrasound on the structure and function of biomacromolecules, specifically protein complexes, have not been extensively studied. This research examines the chemical, physical and mechanical effects of ultrasonic treatment on bovine hide collagen. Scanning electron micrographs show that low frequency, high power ultrasound (20 kHz) appears to unravel the 50 - 100 nm fibrils, seen in ball-milled collagen, into smaller diameter fibrils. Although these smaller fibrils are more susceptible to attack by collagenase, the individual collagen molecules remain intact as demonstrated by SDS-PAGE. Soluble and insoluble collagen and hide powder are also being examined to develop a broader picture of potential effects of ultrasound in leather manufacturing. En ligne : https://drive.google.com/file/d/13jfj1yMy-YFy1efthCdOrWWv0YvbSE_U/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3997 [article]

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