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Soluble silicates in leather production / Karl Heinz Munz in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 159-167 Titre : Soluble silicates in leather production Type de document : texte imprimé Auteurs : Karl Heinz Munz, Auteur Année de publication : 2003 Article en page(s) : p. 159-167 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The treatment of pelts with aqueous solutions of alkali silicates, followed by neutralization, stabilizes them sufficiently for shaving, and so (nearly) native shavings will be obtained. In addition, the application of these silicates improves the exhaustion of later added auxiliaries, especially of chrome tannins. The native shavings can be either composted or utilizable in various ways. This will help the tanners to cope with increasing (European) requirements on disposability of solid wastes. Based on the new experiences, general ideas for improved sustainability are given. En ligne : https://drive.google.com/file/d/1BSE9V7vZbKkcyQhW5pyoRprXqLdt-o_z/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4118 [article]

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Dry heat resistance of hide and leather / Keyong Tang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 168-172 Titre : Dry heat resistance of hide and leather Type de document : texte imprimé Auteurs : Keyong Tang, Auteur ; Jian Cao, Auteur ; F. Wang, Auteur ; Jie Liu, Auteur Année de publication : 2003 Article en page(s) : p. 168-172 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this paper, the dry heat resistance of hide and leather is studied by means of thermal platform microscope. Such factors as drying, tanning, types of tanning agents and tannage degree that may affect the dry heat resistance of hide and leather are included. Changes and mechanisms of samples when dry heated are analyzed and discussed. We use KCrSO4, CrCl3, Cr(NO3)3 and Sugar reduced chrome liquor as tanning agents to study tanning effects on the dry heat resistance of hide fiber. It can be found that chrome tanning may reduce the initial shrinkage temperature, and increase the final shrinkage temperature. It is to say that chrome tanning may broaden the shrinkage range of hide fiber. Dry heat resistance of hide fibers with different degrees of tanning is also studied. Shrinkage ratio of hide fiber tanned with KCrSO4 decreases with increasing KCrSO4 concentration in the tanning liquors. Hide fiber tanned with sugar -reduced chrome liquor posseses the best dry heat resistance in all the four kinds of tanned hide fiber samples studied. En ligne : https://drive.google.com/file/d/1-GYy6UELCOng4wCs7e5IBk7aASQ5CREu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4119 [article]

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Stepping into third millennium : Third generation leather processing : A three step tanning technique / Palanisamy Thanikaivelan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 173-184 Titre : Stepping into third millennium : Third generation leather processing : A three step tanning technique Type de document : texte imprimé Auteurs : Palanisamy Thanikaivelan, Auteur ; T. Ramasami ; Balachandran Unni Nair ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2003 Article en page(s) : p. 173-184 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The do-undo methods adopted in conventional leather processing generate huge amounts of pollutants. In other words, conventional methods employed in leather processing subject the skin/hide to wide variations in pH. Pre-tanning and tanning processes alone contribute more than 90% of the total pollution from leather processing. Apart from this, a great deal of solid wastes like lime and chrome sludge is being generated. In the approach described here, the hair and flesh removal as well as fibre opening have been achieved using biocatalysts and sodium hydroxide at pH 8.5 for cow hides. This was followed by a pickle free chrome tanning, which does not require a basification step. Hence, this tanning technique involves primarily three steps namely dehairing, fibre opening and tanning. It has been found that the extent of hair removal and opening up of fibre bundles is comparable to that of the control. This has been substantiated through scanning electron microscopic, stratigraphic chrome distribution analysis and softness measurements. Performance of the leathers is shown to be on par with conventionally processed leathers through physical and hand evaluation. Importantly, softness of the leathers is quantitatively found to be comparable with that of control. The process also demonstrates reduction in chemical oxygen demand (COD) load by 71%, total solids load by 72% and chromium load by 84% compared to the conventional process. The total dry sludge from the beam house processes is brought down from 149 to 14 kg for processing 1 ton of raw hides. The input-output audit shows that the biocatalytic three step tanning process employs very low amount of chemicals thereby reducing the discharge by 84% compared to the conventional multi step processing. Further, it has also been demonstrated that the process is techno-economically viable. En ligne : https://drive.google.com/file/d/1Y0DaEEJ319MBo2-rfDLS1Oet_zbMfrKl/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4120 [article]

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Further investigations of oxidative unhairing using hydrogen peroxide / Bi Shi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 185-192 Titre : Further investigations of oxidative unhairing using hydrogen peroxide Type de document : texte imprimé Auteurs : Bi Shi, Auteur ; Xingfang Lu, Auteur ; Danhong Sun, Auteur Année de publication : 2003 Article en page(s) : p. 185-192 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The research includes details of hair removal from hide and the influence of hydrogen peroxide on hide/collagen during unhairing process. The results showed that destruction of hair was led by cooperative effect of hydrogen peroxide and sodium hydroxide. The dissolution of hair first happened at hair root, which favors implementation of hair saving system. It was also found that the oxidative effect of H2O2 causes slight protection function of collagen in alkaline medium ( probably, due to cross-linking reaction of collagen induced by H2O2), which is one of the reasons leading to higher tensile strength and lower elongation rate of resultant leather. Isoelectric point of the hide unhaired with H2O2 was lower than that using conventional Na2S unhairing process, due to that more carboxyl or anionic groups were probably derived. Therefore, the chrome tanned leather employing H2O2 unhairing process exhibited higher Cr2O3 content. Based on these observations, the optimal conditions for undertaking H2O2 unhairing, including hair dissolution and hair recovery processes, were presented. En ligne : https://drive.google.com/file/d/1YYxeEr5GHZge4SAz8ObHIq79u9iPWkDk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4121 [article]

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Balancing of properties of veg tan/muf leathers by mixed chestnut/condensed tannins / C. Simon in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 193-195 Titre : Balancing of properties of veg tan/muf leathers by mixed chestnut/condensed tannins Type de document : texte imprimé Auteurs : C. Simon, Auteur ; Antonio Pizzi, Auteur ; B. George, Auteur ; M.-L. Antoine, Auteur Année de publication : 2003 Article en page(s) : p. 193-195 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Recently a process based on the tanning of leather based on the coreaction in situ of vegetable tannins with a new-concept MUF resin during hide treatment yielded leather that had antishrinkage characteristics as good as those obtained by chrome tanning.1-4 Both hydrolysable and condensed tannins were proved to be suitable. This treatment also yielded leather that presented good light- and colour-fastness to UV and visible light irradiation.1-4The combination with aminoplastic MUF resins appears to markedly reduce the photooxydation of vegetable tannins by synergy with the synthetic resin, while still yielding a relatively soft but also tough leather without the need for chrome salts. Leathers prepared with Chestnut or Mimosa combined with MUF tannage in 50/50 and in 75/25 weight ratios exhibited the most promising physical properties. In general polyflavonoid tannins/MUF treatments performed better as regards leather shrinkage temperature than the hydrolysable chestnut tannin/MUF, with mimosa presenting in general a slightly higher shrinkage temperature than quebracho. Conversely, a chestnut/MUF treatment gives by far better colour fastness results and better light stability than all the flavonoid tannins at all levels of MUF addition. The present study reports the results obtained by trying to balance these two properties, namely light/colour fastness and shrinkage temperature. Hybrid chestnut/mimosa mixtures in combination with the MUF resin yield the wanted balance of properties. En ligne : https://drive.google.com/file/d/1Rbnj-9lhfF4LSQ_wMHdXtJYM-8Qufv3K/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4122 [article]

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