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Salt-free chromium tanning : Practical approaches / Murali Sathish in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 1 (01/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 1 (01/2022) . - p. 3-9 Titre : Salt-free chromium tanning : Practical approaches Type de document : texte imprimé Auteurs : Murali Sathish, Auteur ; Rathinam Aravindhan, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2022 Article en page(s) : p. 3-9 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés physiques Déchaulage Opération consistant à débarrasser les peaux de la chaux et des substances alcalines qui leur ont été appliquées au pelanage. Eaux usées -- Analyse Tannage au chrome Tannage sans sels Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chromium tanning finds a prominant place in leather manufacturing for permanent stabilization of hide/skin matrix. Though, it has multiple advantages in terms of high thermal stability, easy process and low cost etc., the current practice is not environmentally sustainable. Poor chromium exhaustion and TDS load generation are the major environmental threats of conventional chromium tanning systems. On the other hand, salt-free chromium tanning is identified as one of the efficient alternative approaches for hide/skin matrix stabilization. However, it has not been commercially practiced due to the several practical difficulties. In this work attempts have been made to develop a practically viable high-performance salt-free chromium tanning system using deliming liquor as tanning float and changing the order of addition of masking salt. The developed methodologies completely avoid the use of salt/basification process and it is suitable for all kinds of raw materials and tannery houses. Besides, the process enjoys 71-77% reduction in TDS load and the uptake of chromium is around 90%. The physical strength characteristics are on par with conventional process and the leathers exhibit good grain tightness and roundness. The developed methodologies are simple and do not require any specialty chemicals. Note de contenu : - MATERIALS AND METHOD : Practical approaches for salt-free chromium tanning - Analysis of wet-ble leathers - Analysis of physical strength characteristics and organoleptic properties - Analysis of wastewater - RESULTS AND DISCUSSION : Approach-1 : Salt-free chrome tanning in deliming liquor (CTDL) - Approach-2 : Changing the order of addition of masking salts (COAMS) - Microscopic analysis - Physical strength characteristics and organoleptic properties - Analysis of wastewater - Table 1 : State-of-the-art technologies for improved chrome tanning system - Table 2 : Process recipe for salt-free chromium tanning in deliming liquor (CTDL) - Table 3 : Process recipe for salt-free chromium tanning: changing the orner of addition of masking salts (COAMS) - Table 4 : Process recipe for conventional pickle-based chrome tanning - Table 5 : Characteristics of wastewater (Deliming to Tanning) DOI : https://doi.org/10.34314/jalca.v117i1.4690 En ligne : https://drive.google.com/file/d/1aI4xzqRNBLiq2uTszet6Vj-1H1yXO16p/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37025 [article]

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Improving tearing resistance of leather - Part 2 - Prevention and treatment of low tearing strength in the tannery / Ricardo A. Tournier in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 1 (01/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 1 (01/2022) . - p. 10-18 Titre : Improving tearing resistance of leather - Part 2 - Prevention and treatment of low tearing strength in the tannery Type de document : texte imprimé Auteurs : Ricardo A. Tournier, Auteur ; Fernando Lado, Auteur Année de publication : 2022 Article en page(s) : p. 10-18 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux -- Séchage Déchaulage Opération consistant à débarrasser les peaux de la chaux et des substances alcalines qui leur ont été appliquées au pelanage. Essais de résilience Neutralisation (chimie) Picklage Le picklage consiste à faire absorber à la peau en tripe une quantité importante d'acide, en présence de sel neutre (NaCl) pour réprimer le gonflement que provoquerait l'acidité du milieu. Post-tannage Résistance à la déchirure Retannage Tannage au chrome Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : An appropriate tear strength is one of the main properties that concern customers and it is also a significant source of claims. The authors make a review of the production process, focusing on each step that can either damage the natural strength of collagen fibers or improve them, and therefore, the leather. The aim of this work, divided in Part 1 and 2, is to transfer field tannery experiences collected over 40 years of activity in different tanneries, to colleagues that are looking for world class leather production. Part 1 has been published in JALCA, 116 (12), 2021. Note de contenu : - 6.0 Deliming - 7.0 Bating - 8.0 Pickling : Tear strength loss estimate - 9.0 Chrome tanning - 10.0 How to select stronger hides - 11.0 Vessels and mechanical action - 12. 0 Post tanning operations : Neutralization - Retannage - Fatliquoring - Drying and softening - 13.0 Final sampling : Tearing, field manual testing - 14.0 Artificial improvement of tearing DOI : https://doi.org/10.34314/jalca.v117i1.4694 En ligne : https://drive.google.com/file/d/1A_NwxO7LxsrXRVQjkrbZDJB19AkXvBKO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37026 [article]

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A cleaner process for short-term preservation of hides using wheat bran / Josep Maria Morera in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 1 (01/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 1 (01/2022) . - p. 19-27 Titre : A cleaner process for short-term preservation of hides using wheat bran Type de document : texte imprimé Auteurs : Josep Maria Morera, Auteur ; Esther Bartoli, Auteur ; Rafael Fernandez, Auteur ; Luisa F. Cabeza, Auteur Année de publication : 2022 Article en page(s) : p. 19-27 Langues : Américain (ame) Catégories : Cuirs et peaux -- Conservation Essais (technologie) Son de blé Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Salting is the most common method to preserve hides and skins. However, this preservation system requires the generation of large amounts of contaminated salt, approximately three million tons per year. In recent years several researchers have suggested different methods for the short-term preservation of hides using plant-based formulations, which either minimize or even completely eliminate the use of salt in the process. In this work, the possibility of using wheat bran for this purpose was studied. Two methods of application (dry and aqueous solution) have been developed. They enable the preservation of hides for one month, reducing by half the salt used in the preservation stage without undermining the quality of the final leather. These two methods contribute to the improvement of the overall sustainability of the tanning process. With dry application, the use of salt is avoided and preservation occurs because the hide is dried. The application in aqueous solution (10% wheat bran) requires its previous hydrolysis and a minimum amount of salt (10ºBé). The preservation occurs because the acidity of the hide is increased. Note de contenu : - EXPERIMENTAL : Materials - Methodology - RESULTS AND DISCUSSION : Test 1. Potential of wheat bran as a hide preservation - Test 2. Influence of saline concentration on the preservation of hides - Test 3. Influence of maceration temperature and the moment in which the salt is added on the preservation of the hides - Test 4. Comparison of the effectiveness of the preservation methods - Test 5. Effect of the type of preservation on the physical properties of the final chromium-tanned leather - Environmental benefits - Table 1 : Summary of tests performed during the research - Table 2 : Comparative pattern. Content of each tube - Table 3 : Comparison of the bacterial growth using the pattern tubes - Table 4 : Results of physical tests DOI : https://doi.org/10.34314/jalca.v117i1.4695 En ligne : https://drive.google.com/file/d/1JJUWx52QfoXLp1mhMV4C2Bii29yf909e/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37027 [article]

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Extract of trema orientalis (L.) Stem Bark : A potential source of environmentally friendly tanning agent for leather industry / Murshid Jaman Chowdhury in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 1 (01/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 1 (01/2022) . - p. 28-34 Titre : Extract of trema orientalis (L.) Stem Bark : A potential source of environmentally friendly tanning agent for leather industry Type de document : texte imprimé Auteurs : Murshid Jaman Chowdhury, Auteur ; Abdur Razzaq, Auteur ; Imran Biswas, Auteur ; Ariful Hai Quadery, Auteur ; Tushar Uddin, Auteur Année de publication : 2022 Article en page(s) : p. 28-34 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Caractérisation Cuirs et peaux -- Analyse Extraction (chimie) Retannage Tanins végétaux Tannage végétal Trema orientalis Trema orientalis est une espèce de plantes arborescentes. Elle appartient à la famille des Ulmaceae ou Celtidaceae selon la classification classique ou à celle des Cannabaceae selon la classification phylogénétique. On le trouve en Afrique du Sud jusqu'en Afrique tropicale ainsi que dans les régions chaudes d'Asie. Il a été naturalisé à Hawaï. Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Researchers around the world are in continuous endeavor to develop environment friendly tanning agent due to adverse effect of conventionally used chromium during leather tanning. Recent trend of tanning is thus heading to chrome-free and greener chemical processing options. Vegetable tanning is an exoteric leather processing technique because of their lower pollution load on the environment. Considering the inadequacy and high costing for the commercialized tannins, development of alternative tannins from locally available plants and their characterizations are important. In this research, the stem barks of Trema Orientalis (L.) were extracted at different temperatures employing water solvent with or without additives (sodium hydroxide or sodium sulphite) to attain phenolic-rich extractives. To ascertain appropriateness as a vegetable tanning agent, the obtained extracts were thereafter characterized in respect to yield, total phenolic content, tannin content and molecular structure. The extraction yield for all extracts improves and the quality remains nearly unchanged with temperature rising. The elevated concentration of chemical additives enhances the extraction yield but lessens the quality of extracts. In terms of extraction yield and the quality of extracts the best condition for extraction was discerned at 80°C with water solvent. This water extract has a decent extent of phenolic and tannin content of 266.13 mg Gallic acid equivalent/ gm of dry extract and 30.12 % respectively. The final extract exhibits excellent leather retanning tendency comparable to the commercial quebracho tannins. Note de contenu : - EXPERIMENTAL : Materials - Extraction process and yield of extract calculation - Total phenolic content determination - Determination of tannin content - Identification of tannin class by FT-IR spectroscopic method - Retanning process of leather - Characteristics of retanned leather - RESULTS AND DISCUSSION : Extraction yield - Characterization of extract - Total phenolic content and tannin content - FT-IR analysis - Characterization of retanned leather - Table 1 : Extraction yield and characteristics of T. Orientalis stem bark extracts and quebracho tannin - Table 2 : Characterization of retanned leather DOI : https://doi.org/10.34314/jalca.v117i1.4696 En ligne : https://drive.google.com/file/d/1qJhz2H1tTtDzYmKke6Qlq9Ry3ElkGsb9/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37028 [article]

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