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Chrome retanning : a study of current methods and an evaluation of a new approach / John W. Mitchell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXVI (Année 1981)
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Titre : Chrome retanning : a study of current methods and an evaluation of a new approach Type de document : texte imprimé Auteurs : John W. Mitchell, Auteur Année de publication : 1981 Article en page(s) : p. 370-394 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Conventional chrome retans are generally inefficient in utilization of the chrome offer. a radically new method, chrome/sulfite/aldehyde (C/S/A), is introduced which shows vastly improved efficiency. Fixation and location of chrome in the leather, along with chrome loss in throaway liquors emanating throughout the retan process, are compared extensively on laboratory and full production runs. Stratigraphic analyses, chrome balances, and leather evaluations were employed. Eleven tables of analysis at key process points are presented. Note de contenu : - INTRODUCTION : Purposes of chrome retanning - Current commercial methods - The new approach
- EXPERIMENTAL : Laboratory scale - Tannery scale - Chemical testing - Physical testing - Chemistry of the C/S/A retanEn ligne : https://drive.google.com/file/d/10fRm9-J_dqFkS3e9fINXEBYhsOAPN3Yj/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17669
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXVI (Année 1981) . - p. 370-394[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 008514 - Périodique Archives Documentaires Exclu du prêt Enzymes in retanning for cleaner blue stock / John W. Mitchell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIII, N° 8 (10/1998)
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Titre : Enzymes in retanning for cleaner blue stock Type de document : texte imprimé Auteurs : John W. Mitchell, Auteur ; David G. Ouellette, Auteur Année de publication : 1998 Article en page(s) : p. 255-260 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This study evaluates the combination of a lipase and a mild protease enzyme to clean the surface of chrome tanned stock of grease, dirt, scud, and other stains, for the purpose of making more uniformly colored leather. A significant reduction was found in grease stains, neck wrinkle discoloration, and other stains. Also , an improvement was observed in the brightness and uniformity of dyeing - backbone to belly and side to side within a mill. This was accomplished using extremely low amounts of a combination of two enzymes selected to be particularly active in the conditions of retanning with respect to pH, temperature, running times, and presence of other chemicals. Note de contenu : - INTRODUCTION: Purpose - Enzymes - Classification - Action - Enzyme specifications - Enzymes for retannage
- EXPERIMENTAL: General application procedure - Evaluation proceduresEn ligne : https://drive.google.com/file/d/1M_ZWatWcGQtTJcyX0QJTEYv82zGFfWJP/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4500
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIII, N° 8 (10/1998) . - p. 255-260[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006968 - Périodique Bibliothèque principale Documentaires Disponible Glyoxylic acid : an interesting contribution to clean technology / Karlheinz Fuchs in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXVIII, N° 1 (11/1993)
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Titre : Glyoxylic acid : an interesting contribution to clean technology Type de document : texte imprimé Auteurs : Karlheinz Fuchs, Auteur ; Rainer Kupfer, Auteur ; John W. Mitchell, Auteur Année de publication : 1993 Article en page(s) : p. 402-415 Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In nearly all countries on earth the protection of the environment has become increasingly a very serious concern. As a result, those producing idustrial and consumer products must strive to reduce environmental strain.
Main causes of concern for tanners are the chrome-containing effluents from chrome tanning, washing, neutralization, retanning, and dying. These have been studies in Hoechst and the authors are pleased to now present a constructive solution: a glyxylic acid pickling process for chrome tanning that considerably reduces the chronium content of tannery effluents (extraordinary fixation, minuscule leaching). It is already well established in many tanneries in Germany, Europe and other parts of the world.
Glyoxylic acid becomes an aid to tanning by converting amine groups in collagen to carboxyl groups, creating additional sites for chrome to combine with the collagen, witch causes the chrome offered to be better exhausted and more strongly fixed than a conventional tannage.
Advantages of the glyoxylic acid pickle include: exceptional chrome exhaustion; leaching is drastically reduced during wringing, washing, and retanning; conventional chrome tanning salt is used; chrome is offered at a reduced level; grain wrinkles level; and it is liquid for automated feed systems.En ligne : https://drive.google.com/file/d/1obRwOG5evU3usqEg3-S-XQMtJdZfuX-Q/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8143
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXVIII, N° 1 (11/1993) . - p. 402-415[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006911 - Périodique Bibliothèque principale Documentaires Disponible Prevention of bacterial damage on brine cured and fresh cattlehides / John W. Mitchell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXII (Année 1987)
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Titre : Prevention of bacterial damage on brine cured and fresh cattlehides Type de document : texte imprimé Auteurs : John W. Mitchell, Auteur Année de publication : 1987 Article en page(s) : p. 372-382 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This study evaluates the effectiveness of the bacteristat 1,2-Benzisothiazolin-3-one (BIT) as a hide preservative. The study is unique in scope in that hide and leather conditions had been evaluated from the hair state through to the crust leather state as the exclusive determination of effectiveness of preservation, since the full extent of damage is often not discernable until hides are processed into crust leather where the grain quality and other properties can be truly evaluated. More than 1300 hides are involved.
The study demonstrates that brine cured hides held one year after treatment with BIT in the raceway are significantly superior in hide and leather quality to those from an untreated raceway. Also it demonstrates that fresh hides treated with BIT in combination with boric acid can be held successfully for twelve days. Finally, BIT was found to reduce fluid exudation which accompanies breakdown of cellular structure, resulting in shrinkage of hide weight.En ligne : https://drive.google.com/file/d/1oj1h8woXF1atHcGutk9iRNddsBDwL__d/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9120
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXII (Année 1987) . - p. 372-382[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 008087 - Périodique Bibliothèque principale Documentaires Disponible Silicone dioxyde : environmentally friendly alternative for wet white manufacture / Karlheinz Fuchs in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXX, N° 6 (06/1995)
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Titre : Silicone dioxyde : environmentally friendly alternative for wet white manufacture Type de document : texte imprimé Auteurs : Karlheinz Fuchs, Auteur ; Rainer Kupfer, Auteur ; John W. Mitchell, Auteur Année de publication : 1995 Article en page(s) : p. 164-176 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Silicon and oxygen are the most abundant elements on earth. When chemically combined they form naturally occuring silicon dioxyde and silicates with widely differing structures. Minerals found in nature and based on these elements are numerous.
Silicates have been widely used in technical applications for a long time. Pure silicon as a material for electronic components laid the foundations of the computer age has had a crucial influence on our era.
In leather manufacture, by contrast, the silicon compounds have so far been of only minor importance. With the development of a specific colloidal aqueous suspension of silicon dioxyde gel, a major step has been taken toward making this class of substances accessible to and usable in leather manufacture.
This compound enables pelts to be processed into wet white, a stabilized hide material that can be subjected to mechanical operations and then can be subjected to mechanical operations and then to any kind of tanning. the hide waste producted in splitting, shaving, and trimming is free from environmentally polluting chemicals and presents no problems in disposal or recycling. Since the collagen is hardly altered by silica (unlike wet white processed with tanning agents that affect the collage fibre structure), subsequently tanned hides retain their charactéristic properties and undergo no adverse changes. This also means no restrictions need be placed on the collagen offal of trimming and shaving, which expands the array of their possible uses and value in the market.Note de contenu : - INTRODUCTION : In the beginning ... the claims - Environmental audit - Wet white economics
- EXPERIMENTAL : Silicon dioxide wet white system - Health and toxicity - Stability of the dispersion
- RESULTS AND DISCUSSION : Influence of pH - Interaction of feliderm W with collagen - Does it tan ? - Further work - How to tan the ECO leatherEn ligne : https://drive.google.com/file/d/18sl4hEUCFj5nc-4xIxu6o9xqmmZr-wyd/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7941
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXX, N° 6 (06/1995) . - p. 164-176[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006932 - Périodique Bibliothèque principale Documentaires Disponible