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Ajouter le résultat dans votre panier Affiner la rechercheAmino resins for leather / Samir Das Gupta in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 63, N° 3 (05-06/1979)
Titre : Amino resins for leather Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 1979 Article en page(s) : p. 49-54 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir
PolyaminesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Amino resins are mainly obtained by the condensation of urea, thio-urea, melamine, dicyandiamide either as single amino base or in mixture of two or more of these with formaldehyde or other lower aliphatic aldehydes. They are either anionic or cationic and are mostly used as retanning agents. Some of them may, however, beused as a solo-tanning agent, particularly for in situ tannage of white leathe or as a pretanning agent. Note de contenu : - Technique of production
- Mechanism of reaction and effect on leather
- Effect on physical properties of leather : Full-chrome side leather - Corrected grain side leather - Retanned sheep skins - Vegetable-tanned EI sheepskins
- Effect on dyeing properties of leatherEn ligne : https://drive.google.com/file/d/10oWOYRUyVnGqZsmsPDkEGU6M1Asb4_gX/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31891
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 63, N° 3 (05-06/1979) . - p. 49-54[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007121 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Innovative tannages for improved leather Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 1987 Article en page(s) : p. 166-184 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : "Innovative Tannages" does not imply that tanners should involve themselves in fundamental research in leather science. What is meant is that there are considerable amounts of fundamental knowledge available through proven research and developments to serve as foundations for an innovative tanner in developing a process to manufacture leather which improved characteristics. In this paper, an attempt has been made to put forward some of those recent innovations in leather science like oxazolidine,polycarboxylic acids for low-chrome & hydrothermally stable leather, chrome-aluminium-polycarboxylic acid for practically chrome free tannages and various applications of fatliquors, for improved leather. En ligne : https://drive.google.com/file/d/1RTacNB8hF1xZTjGCTQLSuHBwv59Tmrv2/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8992
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXII (Année 1987) . - p. 166-184[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 008087 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Minimising the environmental impact of chrome tanning : the "thrublu" process Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 1998 Article en page(s) : p. 15-21 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The commercial chrome tanning of hides and skins complies with conventional understanding and is carried out at pH 2.5 to 4.0. The efficiency of chrome utilisation in many standard systems is between 75-85 %. There are proprietary systems that can be used to increase chrome utilisation but even these options leave chrome in the trade waste discharge and problems of meeting stringent limits remain. The research reported in this paper seeks to minimise the environmental impact of chrome tanning by changing the basis of present chrome tanning technology.
A novel chrome tanning technique for tanning lamb pelts and lime split hides has been developed whereby pickling is completely eliminated and tanning conducted immediately after deliming at pH 7 to 8.8. This novel technique also does not require basification or masking agents for the completion of chrome tanning. This new approach gives a high exhaustion of chrome to be extent of 98 % for lamb and over 99 % for hides with improved yield of leather at reduced cost. Substantial amounts of salt are eliminated from the process and reduced acid usage encourages lower levels of plant and equipment corrosion.
The study has investigated the reactivity of a standard chrome tanning solution by examining the individual reactivities of the constituent complexes inrelation to their charge characteristics.
Development of the novel no-pickle chrome tanning system has demonstrated that the differently charged ionic complexes can all provide a contribution to the tannage,as measured by chrome uptake from solution, and maintain commercially acceptable properties.
A mechanism suggested for the effectiveness of the no-pickle tannage is based on providing a wider pH range for the complex-substrate interaction and reversing the conventional pH trend by starting at elevated pH and allowing the intrinsic acidity of the chrome tanning reagent to reduce the pH to conventional levels.
The no-pickle process has been evaluated in bulk production trials and its advantages confirmed. In a further extension of this research, where pretannage for aqueous degreasing is concluded at elevated pHs that conventionally have required re-acidification for chrome tannage, it has been shown that pH adjustment is unnecessary both in terms of re-acidification and basification.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7937
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 82, N° 1 (01-02/1998) . - p. 15-21[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007020 - Périodique Bibliothèque principale Documentaires Disponible
Titre : A new look at cationic fatliquors Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 1988 Article en page(s) : p. 239-261 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Cationic Fatliquors have been used in the leather industry for a long time, but only as an adjunct to anionic fatliquors,mainly for surface characteristics.
Very few publications give, in quantitative terms, their actual contribution in leather making. In this paper, an attempt has been made to quantify contributions of cationic fatliquors and new ways of applying cationics as primary fatliquors are proposed,particularly for retanned side leather.
Various processes and comparative statistical data on the physical properties of leather, fatliquored primarily with cationic and anionic fatliquors are presented.En ligne : https://drive.google.com/file/d/1P3tvVqRGg1d8go_-5lQuoHTwEKQ0EcIu/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8874
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXIII (Année 1988) . - p. 239-261[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 008088 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Novel eco-friendly approaches for the production of uphosltery leather Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 2009 Article en page(s) : p. 92-102 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In recent years, considerable research has been done to replace chrome tanning with alternative tanning systems. But there are very few methods that are environmentally friendly and cost effective that give leather with performance as good as chrome tanned leather. DasGupta and Debchoudhury reported systems based on oxazolidine and mimosa that gava satisfactory leather with high shrinkage temperature. Vitolo et al reported a tara-aluminum sulphate tanning system as an alternative to traditional chrome tanning. But these are not yet commercially accepted. In this reported a tara-aluminum sulphate tanning system as an alternative to traditional chrome tanning. But these are not yet commercially accepted. In this report, a novel eco-friendly approach for the production of upholsteryleather is given that avoids pickling. The leather is pretanned after bating at pH 7.5-8.5 with 2% oxazolidine E (1-aza-3,7-dioxabicyclo-5-ethyl (3,3,0) octane) to obtain shrinkage temperature around 75-80°C for hides and 80-85°C for skins. These pelts are simultaneously of after treated with 2-3 % replacement syntan. These pretanned hides and skins may be split and/or shaved at this stage, without any difficulty, to the required thickness. This provides opportunities for a tanner to either chrome tan with 4-5% chrome powder 25/33 (25% Cr2O3 content / 33% basicity) following the LASRA ThruBlu systemor organically tan the shaved hides as reported earlier by DasGupta and Debchoudhury.
The splitting and shaving at this stage has the added advantage of lowering the amount of chrome use, very low chrome in effluent, flatter grain, higher area yield of the final leather, and biodegradable chrome-free shavings. This would considerably minimize the disposal problemfor a tannery. The details of these methods are given with performance data to show that the leather satisfies all requirements of modern upholstery leather. The mechanism of the tanning is explained with atomic force microscopy and mass spectroscopy data and the improvement of effluent discharged from a tannery is discussed.En ligne : https://drive.google.com/file/d/10wo0UNZSZTpPYzi09wuMGO7FOVo67XHu/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4480
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIV, N° 3 (03/2009) . - p. 92-102[article]Réservation
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