Assessment of the thermal resistance of leather / Anna Matz in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 68 (Année 1984)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 68 (Année 1984) . - p. 1-7 Titre : Assessment of the thermal resistance of leather Type de document : texte imprimé Auteurs : Anna Matz ; Czeslaw Krawiecki, Auteur ; Miroslaw Mrozowski, Auteur Année de publication : 1984 Article en page(s) : p. 1-7 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Contraintes thermiques Cuirs et peaux -- Propriétés thermiques Evaluation Résistance thermique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A great deal of attention has been paid recently to leathers designed for production of protective clothing worn under "hot" conditions. Several tanning technologies and methods for assessing leather properties have been developed. Relatively few papers have appeared which discussed the phenomena occurring in leather under the influence of heat in an air-dry medium. The practical measure of the leather thermal resistance, which cannot be overlooked in its assessment, is the temperature at which the visible deformation of leather occurs. Depending on conditions in which the leather remains while heated, we may differentiate between (a) the autonomous deformation occurring under the influence of leather-free shrinkage and (b) the deformation under the influence of stresses in leather. The first case of deformation occurs in leathers of small area used in a loose state. Macromolecules, under the influence of heating in such samples, are subjected only to small internal stresses. When affected by a given thermal energy they may increase their entropy and assume the most thermodynamically advantageous shape at a given degree of their crossilinkage. On a macroscale this appears as a certain shrinkage of material. In the case of leathers of greater area or of those used for products with more rigid construction, e.g. footwear, the shrinkage proceeds under slightly different conditions. On a macroscale, the shrinkage does not occur freely as a result of immobilisation of leather edges. On a microscale, the macromolecules have a limited possibil¬ity of changing their shape for they are interconnected by cross-linking. Considering this fact, there tends to be a maximum entanglement of chains, under given conditions, the stresses within the leather being higher the greater the number of macromolecules orientated towards the tested direction which participate in this phenomenon. An outer stress applied to the specimen influences the shrinkage rate and the temperature at which intensive shrinkage begins. The effect of temperature on leathers, under isometric conditions, is a limiting example of the shrinkage to stress ratio. The purpose of our work was to evaluate the thermal resistance of leathers heated in an air-dry medium. The behaviour of leathers heated under free and isometric conditions has been investigated. Note de contenu : - Conditions of test - Examination of thermal resistance of leathers deformed under free conditions - examination of the thermal resistance of leathers undergoing deformation in a stressed state - Cyclic heating cooling of specimens - Changes in leather subjected to constant temperature En ligne : https://drive.google.com/file/d/1xc3X6iSqmmDPSKw6kXXdfr6G8kuHGcbu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34141 [article]

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Effect of acid swelling and its impact on the properties of cow industrial glove leathers / Murali Sathish in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 6 (06/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 6 (06/2023) . - p. 235-244 Titre : Effect of acid swelling and its impact on the properties of cow industrial glove leathers Type de document : texte imprimé Auteurs : Murali Sathish, Auteur ; Palanisamy Thanikaivelan, Auteur ; Nayan Sarkar, Auteur ; Rathinam Aravindhan, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2023 Article en page(s) : p. 235-244 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acides organiques Colorimétrie Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés thermiques Cuirs et peaux de bovins Gants Gonflement (physique) 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 Stabilité thermique Tannage au chrome Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The development of commercially successful salt-free chrome tanning technology is the need of global leather sector to reduce the total dissolved solids in wastewater. Though some attempts have been made to develop salt-free chrome tanning technology, drawbacks such as slow diffusion of chromium, unevenness in softness and other organoleptic properties are the major concern. The generation of localized acid swelling might be a reason for the above drawbacks and no scientific literature available for the same. Hence, it is important to analyze the effect of acid swelling and its impact on the diffusion of chromium, ageing characteristics of wet-blue leather and physical properties of crust leather. The results show that the acid swelling delays the diffusion of chromium in tanning process and also enhances the growth marks on wet-blue leather. The ageing study reveals that the wet-blue obtained from acid swollen system dehydrates faster than the conventional salt based chromium tanning system. In addition, the wet-blue leather from acid swollen system is prone to fungal attack. The industrial glove leather obtained from acid swollen system has reduced strength characteristics viz., 15% reduction in tensile strength, 17% reduction in tear strength and 20% reduction in grain crack/bursting strength. Further, the degree of heterogeneity in softness is high for crust leather obtained from acid swollen system and also more looseness with internal emptiness. Color value measurements reveal that the crust leather obtained from the conventional tanning system is lighter in shade than the acid-swollen system. The results will be useful to design commercially viable salt-free or low-salt tanning systems as well as to tackle the inadvertent industrial scenario where the tanners are looking for solutions for accidental acid swelling and subsequent salvage of the leathers for possible recovery and applications. Note de contenu : - INTRODUCTION : Pickling with non-sweeling acid - Pre-treatment with weak organic acid - MATERIALS AND METHODS : Chromium tanning and post-tanning process - Analysis of thermal stability - Ageing characteristics of wet-blue leather - Microscopic analysis - Physical strength characteristics and organoleptic properties - Color value measurements - Table 1 : Process recipe for tanning the delimed cow pelts - Table 2 : Process recipe for the manufacture of cow industrial glove leather from chrome tanned cow wet blue (Thickness: 1.0-1.1 mm) - Table 3 : Changes in weight of cow pelts and leathers - Table 4 : Changes in thickness and area of cow pelts and leathers - Table 5 : Hydrothermal shrinkage temperature at different processing stages - Table 6 : Physical properties of crust leathers - Table 7 : Organoleptic properties of crust leathers - Table 8 : Color value measurement of wet-blue and crust leather DOI : https://doi.org/10.34314/jalca.v118i6.7657 En ligne : https://drive.google.com/file/d/1oHLiX_RkSCNDjpuZpyhxxvz0C-oPiGFq/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39480 [article]

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Effect of novel synthetic clay on the property of waterborne polyurethane leather finishing agent: enhanced thermal, mechanical and UV-resistant performance / Wang Chunhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 102, N° 3 (05-06/2018)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 102, N° 3 (05-06/2018) . - p. 155-159 Titre : Effect of novel synthetic clay on the property of waterborne polyurethane leather finishing agent: enhanced thermal, mechanical and UV-resistant performance Type de document : texte imprimé Auteurs : Wang Chunhua, Auteur ; Mu Changdao, Auteur ; Lin Wei, Auteur Année de publication : 2018 Article en page(s) : p. 155-159 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Argile Cuirs et peaux -- Finition Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés thermiques Laponite Polymères en émulsion Polyuréthanes Résistance au rayonnement ultraviolet Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Waterborne polyurethane/laponite composites used for leather finishing have been prepared via the solution mixing method. The dispersion stability of laponite and composite emulsions were determined by atomic force microscopy (AFM) and dynamic light scattering (DLS). Thermogravimetric analysis (TGA), tensile testing and UV-Vis spectra were used to test the performance of the resulting films. The results indicate that the nano-particles with negative charges can form highly stable aqueous dispersion under alkaline condition and exhibit good compatibility with anionic waterborne polyurethanes. The emulsions possess good storage stability with an average particle diameter of 80-94nm. The uniformly dispersed clay platelets can markedly improve the thermal stability and mechanical properties of the composites. In addition, the incorporation of small-sized clay is capable of maintaining the transparent appearance of the film and giving an UV-resistant property. Note de contenu : - EXPERIMENTAL SECTION : Materials - Preparation of polyurethane/laponite (LPU) emulsions and films - Characterisation of laponite, WPU and LPU - RESULTS AND DISCUSSION : Dispersion stability of laponite - Stability of polyurethane emulsions - Thermal stability - Mechanical property measurement - UV-Vis spectra analysis En ligne : https://drive.google.com/file/d/1qbu9GWV-X22_dw3rlg9nh36Ku5k4rKOM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30797 [article]

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Hides and humidity / Michaela Schroepfer in LEATHER INTERNATIONAL, Vol. 219, N° 4874 (09/2017)  

[article]  inLEATHER INTERNATIONAL > Vol. 219, N° 4874 (09/2017) . - p. 63-64 Titre : Hides and humidity Type de document : texte imprimé Auteurs : Michaela Schroepfer, Auteur ; Michael Meyer, Auteur Année de publication : 2017 Article en page(s) : p. 63-64 Langues : Anglais (eng) Catégories : Analyse thermique Cuirs et peaux -- Propriétés thermiques Cuirs et peaux de bovins Humidité -- Mesure Tannage au chrome Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The thermal behaviour of bovine skin and wet-blue in varying humidity can be measured by differential scanning calorimetry. The authors discusses the process. Note de contenu : - Materials and mathods - Chromium-tanned collagen - Dry state - Fig. 1. DSC scans of untanned hides at different water contents - Fig. 2. DSC scans of hide collagen tanned with chromium sulphate at different degrees of hydration En ligne : https://drive.google.com/file/d/1Yto3QO8aPrtvnAfBmlOqhXTVwSVlV9o3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29048 [article]

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Hydrogen peroxide-oxidized soybean polysaccharides as novel masking agents for zirconium tanning / Haolin Zhu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 7 (07/2021)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVI, N° 7 (07/2021) . - p. 239-248 Titre : Hydrogen peroxide-oxidized soybean polysaccharides as novel masking agents for zirconium tanning Type de document : texte imprimé Auteurs : Haolin Zhu, Auteur ; Fang Wang, Auteur ; Keyong Tang, Auteur ; Jie Liu, Auteur ; Xuejing Zheng, Auteur ; Qin Shufa, Auteur Année de publication : 2021 Article en page(s) : p. 239-248 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse morphologique Caractérisation Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés thermiques Cuirs et peaux de moutons Granulométrie Oxydation Peroxyde d'hydrogène Le peroxyde d'hydrogène (H2O2), communément appelé eau oxygénée ou encore perhydrol (appellation industrielle), est un composé chimique liquide et visqueux, aux puissantes propriétés oxydantes (il est aussi réducteur). C'est donc un agent blanchissant efficace qui sert de désinfectant et (à haute concentration) d'oxydant ou monergol dans les fusées spatiales. Polysaccharides Les polysaccharides (parfois appelés glycanes, polyosides, polyholosides ou glucides complexes) sont des polymères constitués de plusieurs oses liés entre eux par des liaisons osidiques. Les polyosides les plus répandus du règne végétal sont la cellulose et l’amidon, tous deux polymères du glucose. De nombreux exopolysaccharides (métabolites excrétés par des microbes, champignons, vers (mucus) du ver de terre) jouent un rôle majeur - à échelle moléculaire - dans la formation, qualité et conservation des sols, de l'humus, des agrégats formant les sols et de divers composés "argile-exopolysaccharide" et composites "organo-minéraux"(ex : xanthane, dextrane, le rhamsane, succinoglycanes...). De nombreux polyosides sont utilisés comme des additifs alimentaires sous forme de fibre (inuline) ou de gomme naturelle. Ce sont des polymères formés d'un certain nombre d'oses (ou monosaccharides) ayant pour formule générale : -[Cx(H2O)y)]n- (où y est généralement x - 1). On distingue deux catégories de polysaccharides : Les homopolysaccharides (ou homoglycanes) constitués du même monosaccharide : fructanes, glucanes, galactanes, mannanes ; les hétéropolysaccharides (ou hétéroglycanes) formés de différents monosaccharides : hémicelluloses. Les constituants participant à la construction des polysaccharides peuvent être très divers : hexoses, pentoses, anhydrohexoses, éthers d'oses et esters sulfuriques. Selon l'architecture de leur chaîne, les polysaccharides peuvent être : linéaires : cellulose ; ramifiés : gomme arabique, amylopectine, dextrane, hémicellulose et mixtes : amidon. Rendement en surface Tannage au zirconium Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A series of hydrogen peroxide-oxidized soybean polysaccharides (HPS) were prepared using H2O2 and copper catalyst, which were then used as novel masking agents for zirconium tanning. The HPS samples were characterized by Fourier transforms infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), and X-ray diffraction (XRD). FT-IR suggested the formation of carbonyl and carboxyl groups after hydrogen peroxide oxidation. DLS indicated that the HPS particle size decreases with increasing the H2O2 dosage. HPS with carbonyl and carboxyl groups and medium particle size was able to coordinate with zirconium to remarkably facilitate the tanning process. The shrinkage temperature of the tanned leather reached 92oC. Meanwhile, the fullness, softness, and mechanical properties of the leather were greatly improved by the tanning. The function of HPS and its interaction with zirconium were studied by FT-IR, XRD, and it was found that the triple helical structures of collagen fiber were not changed greatly. Scanning electron microscopy (SEM) showed that collagen fibers were dispersed and tanning agents were evenly distributed in collagen fibers. A new strategy for chromefree tanning is suggested and a strong support for the application of zirconium tanning is provided. Note de contenu : - MATERIALS AND METHODS : Materials - Preparation of HPS - Tanning process - Characterization of HPS Fourier transform infrared (FT-IR) spectroscopy - X-ray diffraction (XRD) - Particle size analysis - Characterization of leather : Thermal and mechanical properties, thickening rate, color, morphological analysis, organoleptic properties and the structures of leather - RESULTS AND DISCUSSION : Structure of polysaccharides - Particle size of HPS - Structure and properties of leather : Thermal properties of leather - Filling effect of leather - Mechanical properties - Color and area yield - Morphological analysis - Organoleptic properties - Tanning mechanism - Table 1 : The zirconium tanning process of pickled sheepskin - Table 2 : Particle size distribution (A-intensity average diameter, B-intensity) of HPS - Table 3 : Mechanical properties of leather samples for different tanning processes - Table 4 : Area yield, chromaticity and color difference of different samples - Table 5 : Organoleptic properties of leather samples for different tanning process DOI : https://doi.org/10.34314/jalca.v116i7.4337 En ligne : https://drive.google.com/file/d/1dbxbSzXyUcLxk3DG0-1emkOrRQp26yeK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36081 [article]

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A novel study on using pufferfish skin as sustainable leather : characterisation, thermal behaviour and sound absorption properties / Muhammet Uzun in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 4 (07-08/2022)  

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Preparation and application of a high exhaustion chrome tanning auxiliary from limed fleshings / Hongjiao Liang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 107, N° 3 (05-06/2023)  

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Preparation and assistant-dyeing of formaldehyde-free amphoteric acrylic retanning agent / Jian zhong Ma in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 3 (Année 2021)  

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Les propriétés spécifiques des cuirs destinés à la chaussure de sécurité / M. Debouit in TECHNICUIR, N° 7 (08-09/1976)  

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Le rôle du finissage dans la protection des cuirs face aux éléments extérieurs / J. Hillion in TECHNICUIR, N° 10 (12/1973)  

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Structural and performance characteristics of pigskin leather with different tanning methods / Nataliia Pervaia in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 3 (05-06/2019)  

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The effect of incorporating hydroxyapatite and silica nanoparticles in polyethylene surface treatment of natural leather / E. Jowshan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 10 (10/2019)  

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Thermal properties of leather and their relation to structural mechanical and handle characteristics in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)  

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Thermophysical and functional-consumer qualities of shoe upper leather / Nataliia Pervaia in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 104, N° 1 (01-02/2020)  

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