Coordinated approach to the production of soft leather / K. Smiechowski in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 89, N° 5 (09-10/2005)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 89, N° 5 (09-10/2005) . - p. 199-203 Titre : Coordinated approach to the production of soft leather Type de document : texte imprimé Auteurs : K. Smiechowski, Auteur ; K. Beleska, Auteur ; A. Zaliauskiene, Auteur Année de publication : 2005 Article en page(s) : p. 199-203 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaux Cuirs et peaux Epilage Extraction (chimie) Granulométrie Huiles et graisses animales Mesure Microscopie Peaux brutes -- Trempe Souplesse (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Production of soft and strong leather requires a coordinated approach to all chemical and physical processing steps. The composition and nature of the fatliquors is only partly responsible for the leather’s softness. Opening up of the structure, neutralization and tanning influence the fatliquoring process and resulting leather as well. Knowledge about the changes of the dermal structure during beamhouse processing and its impact on the reaction of fat with leather is necessary for monitoring the fatliquoring process. Two different methods of opening up of the dermal structure - ‘lime-free’ and ‘lime’ - were used in our experiments to determine the relationship between the parameters mentioned above and the fatliquoring effect. Note de contenu : - EXPERIMENTAL PROCEDURES : Unhairing trials - Fatliquoring trials - Evaluation of fatliquoring effect by extraction of fat from leather samples - Measurement of the particle size of fatliquor emulsion - Microscopy - RESULTS AND DISCUSSIONS : - Table 1 : Dependence of the removed collagenous and non-collagenous proteins on the method and the duration of treatment - Table 2 : Data of fatliquor analysis - Table 3 : Dependence of the amount of extractable and unextractable fats on the method of alkaline treatment and fatliquor properties En ligne : https://drive.google.com/file/d/1LZc2tGKSwpIsdnKzFhJpnqMkcqlyunaY/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39230 [article]

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Lime-free unhairing : part 4 : Influence of unhairing method on dermatan sulphate and microscopical investigation of pelt and leather / E. Kazlauskaite in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 86, N° 2 (03-04/2002)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 86, N° 2 (03-04/2002) . - p. 59-64 Titre : Lime-free unhairing : part 4 : Influence of unhairing method on dermatan sulphate and microscopical investigation of pelt and leather Type de document : texte imprimé Auteurs : E. Kazlauskaite, Auteur ; J. Balciuniene, Auteur ; A. Zaliauskiene, Auteur ; Kestutis Beleska, Auteur ; Virgilijus Valeika, Auteur ; V. Valeikienè, Auteur Année de publication : 2002 Article en page(s) : p. 59-64 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Analyse Epilage Microscopie Sulfate de dermatane Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The article presents the final research into the system containing NaOH, Na2S, and a salt such as NaCl, Na2SO4 or Na2HPO4 and their influence on the properties of pelt and leather. Here are two main pointsof the investigations : the establishment of dermatan sulphate changes during unhairing and the microscopy investigation. It was established that the unhairing method influences the amount of dermatan sulphate in pelt. The method for dermatan sulphate determination was developed and used in this research. The results show that a strongly alkaline action does not increase the removal of dermatan sulphate. As collagen’s chemical and physical changes could be reflected in its structure, optical and scanning electron microscopy analyses of pelt and leather grain and corium were carried out. The micrographs show that the structure of pelt and leather depends on the unhairing method and it differs-differences in opening-up level are observed. These differences are clearly visible and depend on the method of unhairing. The microscopy images confirm the importance of the role of salts, which are added to the unhairing system NaOH+Na2S. Note de contenu : - Improvement of dermatan sulphate determination - Investigation of dermatan sulphate in lime-free unhaired pelt - Grain microscopy - Microscopy of corium - Table 1 : Influence of unhairing method on degradation of collagen and dermatan sulphate En ligne : https://drive.google.com/file/d/14f4WrHFHAsQIcAbi4fhaayMRoSR3Nr8c/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40029 [article]

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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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